The i7-5775C is awesome

[LTC8K6]

I don't know...You can get an 80W Haswell Xeon such as a 1231 V3 for $250. With a Z97 board, it will run all cores at 3.8ghz under load.

That's a lot less than a 5775C.

Or a 65W 4790S for about $300, and it will run all cores at 4Ghz under load.

Is a 5775C really the best value?

 

[ZGR]

I definitely notice that the i7-5775C has a "softer" voltage wall unlike Haswell/Ivy Bridge. On my 4690k, I was getting a massive temperature spike pushing it past 1.3v. On the 5775C, I can probably go to 1.5v+ without much difficulty. I haven't pushed it past 1.45v since that appears to be the safe limit for OCing on air when NOT stress testing. Below 1.4v the chip runs like as if it is on stock settings.

Running LinX would push my Noctua NH D15 to near max fan speed on my 4690k @ 4.4 GHz. On the 5775C, the fans remain at idle @ 4.2 GHz! I almost want to see how low of a voltage I can hit at 4.0-4.1 GHz just to see how cool it is at load. Running LinX at 1.44v @ 4.3 GHz can get the chip to throttle though.

I see this chip as a farewell to a couple of things. This will be my last DDR3 system and my last quad core for desktop. I hope it performs admirably for the next 2-4 years. The next eDRAM chip Intel offers will be the one I want. I hope the E series gets massive amounts of eDRAM soon.

 

[frozentundra123456]

I definitely notice that the i7-5775C has a "softer" voltage wall unlike Haswell/Ivy Bridge. On my 4690k, I was getting a massive temperature spike pushing it past 1.3v. On the 5775C, I can probably go to 1.5v+ without much difficulty. I haven't pushed it past 1.45v since that appears to be the safe limit for OCing on air when NOT stress testing. Below 1.4v the chip runs like as if it is on stock settings.

Running LinX would push my Noctua NH D15 to near max fan speed on my 4690k @ 4.4 GHz. On the 5775C, the fans remain at idle @ 4.2 GHz! I almost want to see how low of a voltage I can hit at 4.0-4.1 GHz just to see how cool it is at load. Running LinX at 1.44v @ 4.3 GHz can get the chip to throttle though.

I see this chip as a farewell to a couple of things. This will be my last DDR3 system and my last quad core for desktop. I hope it performs admirably for the next 2-4 years. The next eDRAM chip Intel offers will be the one I want. I hope the E series gets massive amounts of eDRAM soon.

Maybe BW is cooler running, but sounds like it is partly that you got very lucky in the silicon lottery. Given that though, HW still overclocks higher, does it not?

And I would not hold my breath for edram on E series chips. They have a huge cache anyway, so I dont know if it would show as much benefit.

 

[Keljian]

I run my 5775C @ 4.0GHz/3.7GHz cache/1.8GHz L4 using XTU for the overclock (as my Asrock board doesn't overclock the chip with any form of stability unless you use the predefined overclock settings). The asrock extreme6 being one of the only z97 boards that can do 4xpci-e 3.0 direct to the processor for my 950Pro, for super low latency, lower than the skylake boards - esoteric chip on an esoteric board.

All at stock voltages, but I have disabled the current limiting, so there is no downclocking.

Truthfully I don't need more performance, I just wanted 4ghz.

As for it being better value than the 4790S - it depends. If you need the cache or extra features for a specific application, then definitely. If you don't, then it's a waste of money.

Broadwell has the following improvements over Haswell:
TSX-NI
ADX https://en.wikipedia.org/wiki/Intel_ADX
PrefetchHW
Larger L2 TLB
Faster floating point multiplier (2 cycles quicker - 5 vs 3, so 40% speedup)
Faster Vector Gather
AES-NI speedups
Better branch prediction
Radix-1024 divider
http://www.anandtech.com/show/8355/intel-broadwell-architecture-preview/2

 

[LTC8K6]

Haswell has TSX, it's just disabled due to a bug. Some Broadwell chips have it disabled as well. Some Skylake chips too, I think.

http://techreport.com/news/26911/errata-prompts-intel-to-disable-tsx-in-haswell-early-broadwell-cpus

 

[Keljian]

Haswell has TSX, it's just disabled due to a bug. Some Broadwell chips have it disabled as well. Some Skylake chips too, I think.

Yes. The 5775C has it enabled - All Haswell chips have it disabled (so may as well not have it)

 

[LTC8K6]

Yes. The 5775C has it enabled - All Haswell chips have it disabled (so may as well not have it)

Haswell Xeon E7 V3 actually had the bug fixed.

http://ark.intel.com/products/family/78585/Intel-Xeon-Processor-E7-v3-Family#@Server

 

[PliotronX]

Why does it cost as much as a 5820k? Anyone?

 

[jpiniero]

Why does it cost as much as a 5820k? Anyone?

It's not. It's $8 cheaper at Amazon. :whiste:

 

[ZGR]

It isn't always so expensive. Mine was $333 with shipping included. That is cheaper than a 4790k. It took me awhile to find one below $340. I definitely cannot recommend any quad over $380

 

[Keljian]

It's so expensive because of two reasons:
1. edram on an interposer is not cheap to manufacture - if the ram or the processor are bad, then you have to dump both
2. Z height/tolerances are more challenging to work with.

Is it worth it over the 5820k? again depends on your use case. For my use case - definitely. I rarely need more than 3 cores, but hyperthreading and local cache make all the difference.

 

[Keljian]

Haswell Xeon E7 V3 actually had the bug fixed.

http://ark.intel.com/products/family/78585/Intel-Xeon-Processor-E7-v3-Family#@Server

yes.. you go spend $3k+ for a haswell processor, and probably at least as much for a motherboard, just to get TSX-NI while I have a $300 Broadwell processor and $190 or so for a motherboard which has it

 

[Keljian]

Looks like 4.2GHz is really the wall on this chip. L3 cache also doesn't OC as well, I just left it at 3.6GHz and core at 4GHz. eDRAM is now OCed to 2GHz from 1.8GHz with no effort, max multi is 25 or 26.
.

The reason the L3 cache doesn't OC is pretty simple: it has 6meg of it - for a reason (as explained by intel in podcasts) - this is no accident.

My theory is that the other 2meg is there, it's just used as tag ram for the edram, and as such if you decouple it, then you run into issues.

 

[techne]

Funny article. Why would intel sell a processor with an expensive L4 cache for $350 when it can sell one without the cache for the same money?

Who's money? I can only speak for myself, but if Intel don't offer me a good reason to upgrade, I'll keep using what I already have. Worse than that, I may even feel tempted to go back to AMD in the future. After all, only my main machine is Intel. The other two are AMD.

I really like the i7-5775C and I'm already using a compatible motherboard, but even so, it's not a worthwhile upgrade for me (i7-4771).

 

[Keljian]

Who's money? I can only speak for myself, but if Intel don't offer me a good reason to upgrade, I'll keep using what I already have. Worse than that, I may even feel tempted to go back to AMD in the future. After all, only my main machine is Intel. The other two are AMD.
.

What's to say AMD will give you a good reason to upgrade?

 

[techne]

What's to say AMD will give you a good reason to upgrade?

You mean, another reason to upgrade?

 

[bigboxes]

It isn't always so expensive. Mine was $333 with shipping included. That is cheaper than a 4790k. It took me awhile to find one below $340. I definitely cannot recommend any quad over $380

My 4790K was $250.

 

[biostud]

Why does it cost as much as a 5820k? Anyone?

You get an iGPU for the price of two cores.

 

[Keljian]

You mean, another reason to upgrade?

I'm as big a fan of AMD as anyone, but they have not impressed me since before the c2d, and until they do, I won't jump ship

 

[superstition]

It's so expensive because of two reasons:
1. edram on an interposer is not cheap to manufacture - if the ram or the processor are bad, then you have to dump both
2. Z height/tolerances are more challenging to work with.

Is it worth it over the 5820k? again depends on your use case. For my use case - definitely. I rarely need more than 3 cores, but hyperthreading and local cache make all the difference.

So why is the 5675C so inexpensive? $265 (or whatever) is hardly super-pricey.

Intel could have saved cost by disabling the iGPU and upping the TDP. The cost of the EDRAM isn't enough of an issue to justify banning it as an offering for enthusiasts.

Intel simply did it to withhold the EDRAM to get people to buy bare Skylake and then buy again.

 

[ctk1981]

I don't think the c series was ever targeted at enthusiast, despite its high price. The EDRAM was supposed to help the iris pro iGPU to offset the need for ultra fast ram, much like what AMD apu performance is dependent on. The fact it could be used to help the cpu side was a nice benefit. All in all, the 5775c ended up being a really weird product....glad I own one.

Has anyone used 1.5v ram with their 5775c? One bane of this product would seem to be the necessity for 1.35v ram.

 

[Keljian]

There is no need to use 1.35v ram with the 5775c. I use 1.65v ram, 0 issues

 

[ZGR]

​

I use 1.5v RAM right now. I also ran a 1.65v kit at 2400 mhz @ 1.495v. I could boot up and run some benchmarks up to 2600 mhz 1.65v, but it wasn't stable. 2400 mhz CL11 isn't bad for Broadwell-C I think. But I am returning that kit if the new one I ordered is better.

​

I ordered 1.35v 2133mhz CL11 RAM last week. It was supposed to arrive today, and I had already packaged up the 1.65v kit. The new RAM that came today was a 1.5v kit! Useless. So I am using 1866 MHz CL10 RAM OC'd to 2133 @ 1.5v (My old-old RAM) at this moment. I will see how high the new low voltage kit will OC up to ~1.5v. If I can't beat 2400 MHz CL11 in benchmarks and the games I run, then I will go back to the 1.65v kit and undervolt it back down to a slower speed.
I feel fine running at 1.5v though. No issues. I believe Broadwell-C caps ~2400 MHz DDR3 but I honestly am not sure. I can't find any useful data other than a post FUGGER made on XtremeSystems:

Broadwell 5775C on Phase
System Configurations:

Intel 5775C, C refers to Crystal Well technology that is the 128M eDRAM on the CPU.
This CPU has IRIS Pro 6200, the best iGPU from Intel so far.

Asus Maximus VII Gene
MSI Gaming 7
Gigabyte z97 SOC

Corsair GTX2, GTX3, Dominator Platinum 2666C10

Overclocking Thermaltake 3.0 Ultimate AIO:

Max Frequency of 4.8Ghz @ 1.55v 4c/8t and 4.9Ghz 1c/1t
Max ram speed of 2200Mhz tight timing @ 1.65v
Max iGPU speed of 1300Mhz @ 1.25v
Max ring speed of 4400Mhz at 1.5v

Overclocking Phase -60c:

Max Frequency of 4.8Ghz @ 1.60v 4c/8t and 4.9Ghz 1c/1t
Max ram speed of 2200Mhz tight timing @ 1.65v
Max iGPU speed of 1300Mhz @ 1.25v
Max ring speed of 4400Mhz at 1.5v

XTU 1200 @ 4.7Ghz
Iris Pro FSE scored 900
Aquamark 310,000

Memory:

Broadwell 5250U overclocks the same with memory, you must keep the speed down that you can set very tight. It is the Broadwell IMC.

You can use normal DDR3 voltage but you cannot load XMP profile over 2133Mhz nor can you run over 2200Mhz in speed reliably.

You can run tight timing under the speed limitation.

Iris Pro 6200:

There is not much headroom in the Iris Pro at stock voltages on phase but the scores do increase with this knob being adjusted.

I think there might be several power domains at work here where bios idle is at .200v, desktop is ~ .9v and 3D is ~1.2v. Setting .9 in bios and 1.2v from bios did not boot or locked up at windows loading desktop.

All boards failed at pushing iGPU to or beyond 1300Mhz.

Ring:

The default speed is 3300Mhz @ 0.8v, pushing it up hill it will do 4400Mhz @ 1.5v and more volts did not increase speed on phase.

eDRAM:

There is 128M of L4 cache on the CPU core, this is called Crystal Well technology. I can see where this can be useful if the application can take advantage of it.

The MSI board has the eDRAM divider and the default speed is 1800Mhz and the highest working option is 2Ghz.

Intel sent the eDRAM microcode update at the end of last month and manufacturers are late in creating bios updates. Your board probably does not have an updated bios ready yet for Broadwell with eDRAM.

Conclusion:

http://valid.canardpc.com/4wgfse

Broadwell C is for daily machines, office machines, anything that you are happy at stock speeds or just want to explore the platform. Excellent performance from these chips, I am still exploring the iGPU for a few more days.

​

He did NOT use DDR3L. I was able to hit 2400 Mhz without any problems even after long hours of stress testing. There was always a performance boost from 2133 -> 2400 Mhz in every test (same timings). I definitely had problems at 1.65v though. Sometimes the system wouldn't POST until I pressed the MEMOK! button to reset the RAM back to 1.5v 1333 MHz. I will find out next week if a lower voltage will enable higher clocks. If not, oh well. I am having fun tinkering around.
When I get my low voltage kit I will hopefully be able to go past 2400 MHz (albeit at slower timings most likely) below 1.5v. If not, I think I will go back to the undervolted 1.65v kit. It could go as low as 1.48500v @ 2400 MHz CL11 before causing problems.

​

I definitely wouldn't go with 1.65v RAM (at the super high clockspeeds I was running at least) , but then again, we really don't know? This whole "Don't use 1.65v" thing is about Skylake DDR3 which is a minuscule amount of users. The Broadwell IMC is definitely different than Skylake's but I really don't wanna push it to find out. It is tempting to pay a $200-300 premium for an XMP 2133 MHz CL8 kit and call it a day... But that is boring. Another idea is to buy older 1.2v DDR3 but that sounds like a waste of time.

Broadwell-C DOES scale to 2400 Mhz though. I got solid 5-7% gains going from 1866 CL9 to 2400 MHz CL11. In games like ARMA and Sins it was a bit more. Broadwell-C is meant for excellent single threaded throughput. The fastest RAM I can get will help me in my CPU bottleneck problems.

edit: What is Broadwell's IMC voltage limit? Is it Haswell's 1.7v? (Max safe spec from intel). I really can't find this info. 1.65v @ 2400 MHz CL11 CR 1 is just as stable as it is at 1.5v. All the mediocre reviews online mostly used DDR3 1600. Every mainstream CPU review online gimps memory. They just say it supports DDR3L and off they go running the tests. The performance gain from 1600 -> 2400 is quite significant.

 

[ctk1981]

Thanks for the info. Currently I'm loaded with 32gb of 1.35v ddr3 1600. I'd like to try faster ram but common sense tells me if it ain't broke don't fix it.

 

[ZGR]

Just got my new DDR3L RAM in the mail. Previously, I've been rocking 1.65v -> 1.5v @ 2400 MHz CL11-13-13-35 CR 1T.

I was able to confirm that I cannot be stable beyond 2400 Mhz with a command rate of 1T.
The new kit is a 4x8gb kit to max out my RAM. I am able to achieve CL11-13-13-31 CR1T @ 2400 Mhz 1.38v. Trying the same settings at 1.35v causes stability issues.
I am able to boot up with the timings 10-12-12-31 @ 2400 Mhz, but only with the CR of 2T. All in all, I guess I am done with RAM on this platform.