DDR2::::better to run in one channel or two?

[beermug]

Hi


I consider myself to be a middle of the road guy when it comes to computer knowledge, all book learned. However, im not too experienced in the "low level stuff".
I wanted to expand to 8GB memory, so i bought another 4GB kit of the Reapers [when OCZ still made memory] and tried to install. To my dismay, the comp would not boot. Now this memory required bios adjustments to run which i had already done when installing the first 4GB. Changed memory voltage from 1.8 to 2.1v as per OCZ, and also played around with the timings a little to get the desired 533mhz to achieve 1066mhz.
After ALOT of emails and searching online i found out that AMD cpu's had a limitation [the cpu internal memory controller is designed to run memory at 1066 or higher speed "only in one channel"!! P.O.'d i returned the second 4GB kit to the vendor, and continued running only 4GB to this day.
Since that time i have made some changes in habit when using the pc. I spend alot more time running streaming video at times i might run as many as 2 or 3 in 2 different browsers, until i started getting BSOD's.....................................
So, im thinking its one of two things. Either my mainboard design cant handle the load of all that data demand, or , i need more memory.
Now i find out that OCZ is out of the memory business so im left to finding some of the slim pickins on Ebay. Or go to a different brand.
I had an idea, noticed that a couple of manufacturers still make 4GB sticks of DDR2 pc-8500 memory. Im curious if i can use 2 of them to make a total of 8GB running in one channel [which would replace my current 4GB of OCZ Reaper memory].
Or, do i need to get 8GB of pc-6400 800mhz and run the pc slower than before, but be able to make use of both channels [i.e. 2GBsticks x4 slots]?

Any idea as to which direction i should go on the memory?

Sorry for the long winded story but i thought explaining my case would be of some use. ()

Gigabyte GA-MA790GP-UD4H board
AMD Phenom II x3 2.5Ghz cpu [3cores]
OCZ Reaper PC-8500 1066mhz memory 4GB kit in single channel @ 2.1volts
Asus EAH5670 video adapter 775mhz 400stream processors 128bit 1GB GDDR5
Asus Xonar DX sound card
Western Digital Caviar Green 500GB Hard Disk
**Windows7 ultimate 64bit**
Thermaltake 450watt PSU

 

[Cerb]

Zeroth, you are running Windows Vista 64-bit or Windows 7 64-bit, right? Just want to make certain.

First, there's also a chance your PSU is giving you problems, but there isn't any good way to test that without getting another PSU, just like there isn't a way to verify the memory is going bad without replacing it, too. Given that it's high-voltage overclocker memory from a few years ago, though, I'd bet on the memory any day. That 2.1V did not invalidate the warranty does not mean it was good for the chips.

Run of the mill G.Skill, A-Data, Corsair Value Select, Crucial, etc., will work just fine, and should do so at the proper 1.8V.

Officially supported SKUs are long gone, and the supported list is small, anyway. Personally, I would get two sets of these, fill all the slots, and run memtest86+ overnight (assuming it makes it through 1 pass), with all default settings. If you wake up to no errors, use it. Otherwise, come back here.

2x4GB DDR2 is significantly more expensive, from reputable companies, as are 4x2GB kits. While you can find a measurable difference by using faster RAM, it won't be by that much.

 

[MobiusPizza]

You are confusing youself about channels? If you have 2 sticks you will be running 2 channel (if you plug in the recommended same colored slots on the motherboard)
Well if your question is single stick PC2-8500 vs PC2-6400 dual channel (dual stick), well the fact is it won't matter too much. Dual channel even slower bin RAM should have a slight advantage though.

Any problems with the support of 8GB RAM if any is either:
1) Check your motherboard specification if 8GB is supported
2) Reduce RAM timing and command rate (from 1T to 2T) and/or run at a lower RAM frequency and see if it works
3) You cannot overclock your CPU by as much of a margin if you populate all 4 slots of the RAM slot. But 2 should have been fine, in any case disable any overclocking first.
4) Make sure all RAM support the voltage you are driving them. Try not to mix and match different voltage RAMs. It's also said it's preferrable not to mix vendors even.

 

[dorion]

Run your memory at DDR2-800 you will not notice the loss in performance. With that you should be able to run 4 DIMMs. You should also have no problem running two different kits, but your old kit will be the limiting factor in how low you can run the voltage

The other alternative is to get a newer processor like the x4 965, which is when they fixed the DDR2-1066 DIMM limitation.

Oh another alternative, overclock the NB to something like 2400Mhz.

Spend more money and go to an AM3 MB and some nice cheap DDR3.

Don't spend money on 4GB DDR2 DIMMs.

 

[Itchrelief]

I'd go with what Cerb says. I don't think that just running low on memory will trigger a blue screen with no warning. Maybe if you turned off the swap file but I'm not sure.

Something's either physically wrong with one of your components (overheating, dying RAM, dying PSU, etc.) or you've got a bad driver or data corruption on your drive.

To check the memory, run memtest86 or try pushing F8 on boot to get to the Windows recovery mode and run the windows memory check tool. If it finds problems you'll probably have to replace your current RAM and not just buy additional sticks.

 

[Cerb]

I'd go with what Cerb says. I don't think that just running low on memory will trigger a blue screen with no warning. Maybe if you turned off the swap file but I'm not sure.

Nope. Windows will tell you the program ran out of memory, or that it couldn't allocate more, and just the one offending program will either gracefully quit (if coded for that scenario), or crash.

 

[beermug]

Thanks for the info Dorion.
did a little research and checked on that C3 stepping modification to the internal cpu memory controller. According to AMD and PhenomII with C3 should support 1066Mhz with 2 sticks in dual channel. The motherboard supports the 2.1volts needed for the memory.
So, i can change to a C3 stepping cpu and add another 4GB of the Reapers [providing i can find some probably on Ebay].

by the way i also noticed some price drops on the PhenomII's and was curious. IT seems that AMD has in their infinite wisdom decided to start producing those cpu's without an L3 cache!!!! model numbers are same, part number is different [and price]
with L3 cache WDX955FBGMBOX
without L3 cache WDZ955FBGMBOX

 

[Cerb]

Don't bother upgrading the CPU. 800MHz DDR2 will be <5% slower for 99% of usage. Replacing the CPU, then getting RAM, is just not worth it. New good Phenom IIs cost too much, old ones don't sell for enough, and Intel's low-end CPUs are so much faster for most uses. Unless you have a way to use 6 cores all at once, you wouldn't get your money's worth out of an upgrade to another Phenom II.

If you plan on keeping the PC for awhile, and 4GB is limiting, replace/upgrade the RAM to 8GB, and leave it at that. Maybe overclock your CPU a bit (if you want to overclock it quite a bit, good CPU coolers can be had for <$30), and/or unlock cores, if it's possible with that mobo. If you plan to upgrade sometime in the near future, get 4GB of a reputable brand's memory rated at 1.8V, and save up.

The issue with the memory voltage is not about motherboard support for voltage, but that all standard DDR2 was really made for 1.8V, which is the JEDEC spec voltage. Memory rated higher than that is being overvolted. Some can take it, some can't, and some seem to take it for awhile but die after awhile. If you want to be sure not to revisit this kind of problem in the future, stick to DDR2 rated at no more than 1.8V; and if upgrading soon, that'll be 1.5V for DDR3.

 

[MobiusPizza]

What Cerb saids
RAM performance is just not very important on CPUs with integrated memory controller, i.e. most CPUs nowadays.
0-5&#37; performance variation for different RAM frequency bins and it's closer to 0 most of the time.