APU Wars - Ongoing APU Review by AtenRa

[Shivansps]

Can you try to undervolt the A8-7600? i evaluating a A8-7600 for HTPC/NAS, since A88X chipset has 8 SATA built-in.

 

[DrMrLordX]

I undervolted my 7700k. NB undervolting was not effective, but I run vcore at 1.075v @ 3.4 GHz. Turbo is deactivated.

 

[myocardia]

I undervolted my 7700k.

What do you use this 7700k to do, HTPC?

 

[DrMrLordX]

Just general desktop use. I undervolted it for the heck of it, to see how far down it would go. Since the vcore went so low @ 3.4 GHz I saw no reason to underclock it.

For "serious" performance (benchmarks, or the occasional game that benefits from it) I jack the speed back up to 4.5-4.7 GHz depending on how much voltage I want to feed it and the intended duration of the overclock. But for general usage, there's very little reason to run up the clockspeeds.

 

[Abwx]

I undervolted my 7700k. NB undervolting was not effective, but I run vcore at 1.075v @ 3.4 GHz. Turbo is deactivated.

That s about 35% lower TDP than at stock voltage, as much as what would be provided by a node shrink...:biggrin:

 

[TeknoBug]

Can you try to undervolt the A8-7600? i evaluating a A8-7600 for HTPC/NAS, since A88X chipset has 8 SATA built-in.

Before I got rid of my A8 7600 I set the TDP to 45W, you can probably go further with certain motherboards.

 

[DrMrLordX]

double post. Blar.

 

[DrMrLordX]

That s about 35% lower TDP than at stock voltage, as much as what would be provided by a node shrink...:biggrin:

I would assume that actual power usage is based heavily on how much I use the iGPU, since vNB is at 1.05v and can go no lower, which is not that far off from the 1.10-1.15v that people usually get for stock vNB. I almost got lower vNB to work, but it was a hair unstable.

The other xfactor with my undervolt is the cooling. The CPU temperature reported by the UEFI sits at +1C over ambient idle/+4C over ambient at load. The most I can move thermal margin is about 2 units, running Prime95 768k/768k, inline FFTs. A stock cooler could not do that, but "extreme cooling" can. With inferior cooling, temps could get higher, pushing up the minimum operating voltage. The powerful fans involved assure that there is no actual power savings from running the CPU at such a low voltage. I do it just for kicks, and to extend the life of the processor in circumstances when 3.4 GHz is "good enough".

Before I got rid of my A8 7600 I set the TDP to 45W, you can probably go further with certain motherboards.

Asus boards seem to have good voltage controls. The A88x-Pro, Crossblade Ranger, and possibly the A88x-Plus have nice digital VRMs that do a good job of satisfying Kaveri's finicky need for stable voltages. You could probably get good-to-very-good results with a Gigabyte UP4 as well.

 

[Abwx]

I would assume that actual power usage is based heavily on how much I use the iGPU, since vNB is at 1.05v and can go no lower, which is not that far off from the 1.10-1.15v that people usually get for stock vNB. I almost got lower vNB to work, but it was a hair unstable.

Actualy i was talking for a 100% CPU usage with the GPU at 0% and with X264 encoding, a task where Kaveri throughput is quite good and hence will load it adequatly, for CPU + GPU in games the chip consume less apparently as full CPU frequency is not required to fully load the GPU.

As for voltages the rule is at least 10% voltage margin, for a chip that get down to 1.050V with Prime 95 that means setting the voltage at 1.155V, preferably something like 17-18%, FTR servers chips are at 20%...

The powerful fans involved assure that there is no actual power savings from running the CPU at such a low voltage. I do it just for kicks, and to extend the life of the processor in circumstances when 3.4 GHz is "good enough".

Kaveri is very efficient up to 3GHz, above this frequency the things start to degrade slowly but surely, perf/watt can be improved without undermining too much the perfs by setting 3GHz base/3.5 turbo rather than a fixed 3.4GHz frequency.

Asus boards seem to have good voltage controls. The A88x-Pro, Crossblade Ranger, and possibly the A88x-Plus have nice digital VRMs that do a good job of satisfying Kaveri's finicky need for stable voltages. You could probably get good-to-very-good results with a Gigabyte UP4 as well.

Frankly i dont know about MBs precisely, the ones you re pointing seems redundant here and there, there s also Asrock that do some nice ITXs, at somewhat inflated prices, though.

 

[weeber]

I undervolted my 7700k. NB undervolting was not effective, but I run vcore at 1.075v @ 3.4 GHz. Turbo is deactivated.

Wow, I just built my 7700k HTPC last weekend and apparently need to try decreasing my voltage some more. I was able to overclock the iGPU to 800Mhz easily, but still running vCore @ 1.25. Since I'm running the stock cooler, my main interest is dropping voltage but maintaining stock clocks.

OTOH, I may also try Abwx's suggestion of setting it to 3GHz base clock and see how low it will go. Looks like more tweaking is in my future...

Anyways, great info in here.

 

[DrMrLordX]

Frankly i dont know about MBs precisely, the ones you re pointing seems redundant here and there, there s also Asrock that do some nice ITXs, at somewhat inflated prices, though.

The ones I mentioned just happen to be very good motherboards with nice features in the UEFI. Well okay, the UP4 has been panned for having a poor UEFI, but I digress. All except the Plus are excellent OC boards, whereas the Plus is a pretty good OC board at a low-ish price.

I would not trust many of the Asrock FM2+ boards, with the possible exception of the Killer.

Wow, I just built my 7700k HTPC last weekend and apparently need to try decreasing my voltage some more. I was able to overclock the iGPU to 800Mhz easily, but still running vCore @ 1.25. Since I'm running the stock cooler, my main interest is dropping voltage but maintaining stock clocks.

OTOH, I may also try Abwx's suggestion of setting it to 3GHz base clock and see how low it will go. Looks like more tweaking is in my future...

Anyways, great info in here.

A lot of it will depend on CPU temps. Sure, lowering voltage can lower temps (which in turn lowers minimum operating voltage, albeit only by a very small amount), but you will hit a wall eventually based on your cooling. If you are satisfied with 3 GHz, then 1.05v-1.1v is probably doable with the stock cooler in an unremarkable case.

Also, the x-factor is the iGPU which can heat up the the cores when active and mess with stability.

As a general rule, I would not recommend trying to push your vcore below your vNB, and I would definitely do any CPU stability tests with and without simultaneous iGPU load (be sure to disable p4 and p5 states with amdmsrtweaker before doing this) to see what happens.

 

[YBS1]

Does there seem to be a consensus on what would be the best overclocking mini-itx board for the 7870K? Not that I wouldn't give up some overclock-ability for a better rounded board if it were an either/or situation. I wouldn't really plan on running this on the ragged edge anyway, more like a general entertainment toy/HTPC.

 

[AtenRa]

@ YBS1

The Gigabyte GA-F2A88XN-WIFI and the MSI A88XI AC V2 are among the best mini-itx FM2+ boards.

 

[YBS1]

Yeah, the MSI board was the one I was looking most closely at. Truth be told I have an irrational desire to have an FX9590 but there are no mini-itx AM3 boards. Since I don't really plan on doing any heavy gaming on the box the 7870K would save me the cost of a discrete graphics card anyway.

 

[TheELF]

the 7870K would save me the cost of a discrete graphics card anyway.

Not really,compare the price to an x4 860 ,add to that the price of dual channel memory,so at least 2 4gb sticks since you will loose about 1,5-2gb to the vga,you will only have a ddr3 vga no option for gddr5,and the price of a stronger mobo that can handle both the cpu and the vga through the cpu slot,
you are pretty much better of buying a discrete cpu and discrete vga,might be a bit more expensive but having 8gb for system and separate 2gb gddr5 mem for your vga plus having less stress on your mobo/cooling is well worth it.

 

[YBS1]

Not really,compare the price to an x4 860 ,add to that the price of dual channel memory,so at least 2 4gb sticks since you will loose about 1,5-2gb to the vga,you will only have a ddr3 vga no option for gddr5,and the price of a stronger mobo that can handle both the cpu and the vga through the cpu slot,
you are pretty much better of buying a discrete cpu and discrete vga,might be a bit more expensive but having 8gb for system and separate 2gb gddr5 mem for your vga plus having less stress on your mobo/cooling is well worth it.

I can see your point but this is one of those cases where simplicity is the best course of action. It's going into an NCASE M1, I originally bought the case with the intention of building a mini-itx powerhouse (4770/4790K, Asus Maximus, whatever top single gpu at time, etc) to be used as my main pc. I however got distracted and went entirely in the opposite direction with a X99 Case Labs monster. At this point I'm just wanting to build out the mini-itx with something suitable to hookup to the TV in the den for light steambox-ish gaming and HTPC usage. I mentioned the FX9590 above because that would be the only situation I would be willing to spend considerable money on it, just the novelty of stuffing that high TDP monster into a mini-itx platform would be totally worth it! Sadly, there is no such AM3+ boards. I can just about assure you though once Skylake-E or something comes out to give me the upgrade itch, my 5960X is going to find it's new home stuffed into one of these. Weeee!

 

[DrMrLordX]

Not really,compare the price to an x4 860 ,add to that the price of dual channel memory,so at least 2 4gb sticks since you will loose about 1,5-2gb to the vga,you will only have a ddr3 vga no option for gddr5,and the price of a stronger mobo that can handle both the cpu and the vga through the cpu slot,
you are pretty much better of buying a discrete cpu and discrete vga,might be a bit more expensive but having 8gb for system and separate 2gb gddr5 mem for your vga plus having less stress on your mobo/cooling is well worth it.

You are missing a few points:

1). There are no GV-A1 stepping 860k chips out there (870k isn't out yet). GV-A1 is going to have better voltage scaling all the way up to the wall, which for Kaveri refresh is around 4.7 GHz. KA-V1 can get there some of the time, but will usually require more voltage to get there.

2). You're going to want dual-channel memory for an 860k anyway. You're also going to want to make sure it's dual-rank, which often requires you to buy 8 gig DIMMs to make sure of that. Finding 4 gig DIMMs in dual-rank form now is rather difficult, though not impossible.

3). Under most circumstances, allocating more than 1 GB of RAM to the iGPU on Kaveri/Kaveri Refresh produces lower performance. You will lose around 1.1 GB of usable RAM (I have 14.9 GB on my A10-7700k with 1 GB allocated out of 16).

4). Unless you're pushing for the absolute highest overclock on everything (CPU + iGPU) with a 7870k, you will not need something like the Crossblade Ranger to run it. An A88x-Plus should do nicely, and it can be had for around $60. I would recommend the same for a budget-minded 860k overclocker.

The main downside of the 7870k is that you have to remember to "undervolt" it for anything but the most extreme overclocking. Most boards will push 1.45v vcore or higher by default!

 

[YBS1]

I ended up picking up a 7850K instead of the 7870K, with promo code it ended up being $25 cheaper. Paired it up with an ASRock FM2A88X-ITX+, it came out about ~$20 cheaper than the MSI and Gigabyte and I didn't see any obvious advantages in those two over the ASRock other than they both had wireless AC where as the ASRock only has N. The rig will be placed directly next to a Wireless AC bridge anyway so this was of no consequence.

The funny part to this story is I waffled back and forth between this and the ASRock X99 mini-itx board and a 5820K (I also stalked NewEgg on Skylake release day for a 6700K and compatible Z170 mini-ITX board but that was fruitless thankfully), talk about dissimilar competitors huh? My reason being when I moved on from the 5960X I currently use in my main pc I could just move it over to the HTPC. In the end though I remembered what this was primarily going to be used for and opted for the more sensible solution. I did splurge on the power supply unit though and opted for the 600w SFX Silverstone just for possible future proofing. I've not put together an AMD system for personal use in quite some time, should be fun.

 

[DrMrLordX]

Good luck! I'm not sure how that board will handle, but be sure to monitor the "default" voltage levels carefully. Your chip shouldn't require more than 1.3v across the entire turbo range. Even older UEFI revisions were pushing ~1.36v or more for the top turbo states.

Unless you plan on overclocking, you should be able to reduce voltage to deal with any shortcomings of the VRMs or socket, avoid cTDP throttling, etc.

 

[YBS1]

Good luck! I'm not sure how that board will handle, but be sure to monitor the "default" voltage levels carefully. Your chip shouldn't require more than 1.3v across the entire turbo range. Even older UEFI revisions were pushing ~1.36v or more for the top turbo states.

Unless you plan on overclocking, you should be able to reduce voltage to deal with any shortcomings of the VRMs or socket, avoid cTDP throttling, etc.

I'll probably overclock just to see what she's got, then drop it back to default or wherever above that feels comfortable. Thermals shouldn't be a problem, I've got an H80i and H100i at my disposal, the VRMs are said to roast on this board though, I may stick some sinks on them.

 

[Madpacket]

Yeah, the MSI board was the one I was looking most closely at. Truth be told I have an irrational desire to have an FX9590 but there are no mini-itx AM3 boards. Since I don't really plan on doing any heavy gaming on the box the 7870K would save me the cost of a discrete graphics card anyway.

Nice thread, just thought I would add a few comments from experience.

I had all three ITX top FM2+ boards (MSI, Gigabyte and AsRock, dropped the Gigabyte board during a test and killed it). From my testing the Gigabyte had the best memory bandwidth measuring with Sandra at the same speeds as the other boards but I couldn't get 2400mhz stable (tried three different sets of 2400 mem including AMD's own 2400 rated memory). With mild BCLOCK adjustments I ended up around 2240mhz and ended ip around 15200 in the Sandra mem bandwidth tests but it proved unstable (HDD corruption etc). The Gigabyte also has better heat-sinks over the VRM's compared to the MSI.

The MSI has kind of a strange and tight component layout and (mine) came with a dead NIC. It also won't allow running non K processors at 2400mhz, it locks for example my 7600 and 7800 to 2133mhz as a max memory setting even with AMD 2400 memory which is disappointing but the board allows me to run the GPU at 900mhz no problem. It also has very nice range of voltage settings (you can set 1W increments between 45 and 65w) compared to the other boards which are only static 45, 55 or full. I ended up using my MSI board paired with my 7800 for my main HTPC all stuffed in a Silverstone Milo ML06 but overall I don't think it deserves the asking price.

I think the ITX AsRock is the best board overall, although it lacks heatsinks over the VRM it has the nicest component layout considering what it comes with and it runs 2400mhz on all three chips (7600, 7800, 7850K) which sort of makes up for the memory performance deficiency compared to the Gigabyte board and appears to have the most flexibility in changing of BIOS settings. For the VRM cooling just use a heatsink and fan that blows air over the VRM components and you should be fine unless you're really pushing it. It also has neat things like HDMI in so you can daisy chain another computer or gaming console through it if you're short on HDMI ports. Probably the best board if you want to make a NAS / HTPC small Fractal Design Node 304 as it has 6 SATA ports (Node 304 can handle 6 full size drives). I believe the AsRock was also the cheapest of the three boards.

It's too bad Asus doesn't offer an ITX FM2+ board as I find Asus boards have an easier time with different memory types and high speeds.

Just wanted to add my experiences in case others' are looking at these. FYI the 7800 runs most of my Steam library just fine at low or medium details and works great as a entry steam box. I haven't come across a game it can't really handle yet other than Hatred (which is a terribly unoptimized game). GTAV and the Witcher 3 are surprisingly playable on it. I just upgraded recently to Windows 10 on the MSI and it appears to have helped smooth out frame-rates a little but it could be placebo.

I should state that even with the poor memory overclocking, the Gigabyte board had the best bandwidth and may be the best board if you really want to push the clocks up. It seems the best built, the most solid of the three.

 

[YBS1]

Well it's up and running, though not how I had hoped. Lack of planning put a damper on proper assembly, so it's basically in limp mode right now. It should have dawned on me I wouldn't be able to run an H80i in push/pull with so little clearance. Thankfully AMD provided a little rinkey dink hs/fan for the time being. I also didn't take in consideration the amount of sata power connectors I was going to need versus how many the Silverstone psu provided. I'll have to dig up/buy a couple of splitters. Still waiting on my mini-sata to sata cable as well for my slim line bd-r drive, and to beat it all I found out my NCase M1 didn't come with as many 2.5 drive mount screws as it was supposed to. Bah!

 

[burninatortech4]

Well it's up and running, though not how I had hoped. Lack of planning put a damper on proper assembly, so it's basically in limp mode right now. It should have dawned on me I wouldn't be able to run an H80i in push/pull with so little clearance. Thankfully AMD provided a little rinkey dink hs/fan for the time being. I also didn't take in consideration the amount of sata power connectors I was going to need versus how many the Silverstone psu provided. I'll have to dig up/buy a couple of splitters. Still waiting on my mini-sata to sata cable as well for my slim line bd-r drive, and to beat it all I found out my NCase M1 didn't come with as many 2.5 drive mount screws as it was supposed to. Bah!

I run my h80i in push only in my node 304 with a gigabyte a88x wifi. Seems to work ok.

 

[Abwx]

It should have dawned on me I wouldn't be able to run an H80i in push/pull with so little clearance. Thankfully AMD provided a little rinkey dink hs/fan for the time being.

FWIW the 7870K has the same cooler as the 125W FXs, depending on the $ difference with a 7850K it could be often a better choice.

 

[YBS1]

I run my h80i in push only in my node 304 with a gigabyte a88x wifi. Seems to work ok.

The node is quite a bit wider than the M1, I went back and tried to squeeze it in again as push only and did manage to contort it in a way that it fit. I was pretty happy with myself and was in the process of reassembling it when I noticed from above that both lines running from the radiator where effectively crimped shut due to the angle they had to be bent. Scratch that, not wanting to pull the H100i off my 3930K just yet (for anyone wondering the H80i has a thicker radiator than the 100 series), my last resort was an original version H60 I had stashed away. This went much better.

I haven't done anything in the way of playing with voltages or anything other than set it up by defaults so far, but using the ATuning software to change the multiplier it was running through benches fine at 4400MHz showing ~1.31V. How much voltage is deemed safe here, and roughly where is the temperature ceiling you don't want to cross?