can i run 6400 and 8500 ddr2 together?

bazmo

bazmo

bazmo

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6 Oct 2008
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57
Hi,

I was wondering if someone could clarify this for me?

I currently have 4gigs corsair dominator 8500 DDR2 (2x2gig sticks), and have run out of memory so I was going to buy another 4 gig. Given the fact that I'm running the RAM at 800mhz (not 1066), can I just buy some cheaper 6400 sticks and put them in? Or does it all need to be consistent?

Many Thanks
 
ah ok thanks for the reply.

motherboard is an Asus P5Q-E and the prcessor is Q9550. The only reason I'm not running at 1066 is because the bios defaults to 800 and I didn't want to mess around with the voltages and stuff
 
You probably could, but buying it is the only way to be sure! There may be incompatibilities, and usually you would have to increase voltages a little to match the sticks, or because there is more strain on the memory controller.
 
bazmo said:
ok no probs, I think i'll just spend the extra 15quid - sounds like more hassle than its worth!

Its not a problem to match different brands together though is it? It seems impossible to get hold of dominator 8500 anymore! :( If I buy http://www.overclockers.co.uk/showproduct.php?prodid=MY-039-KS&groupid=701&catid=8&subcat=817 will this be ok?

Thanks again for the replies
Click to expand...

Yeah it'll be fine.

You may need to increase voltage slightly though because of running extra sticks.
 
I have 2 x 2GB sticks of Corsair 8500 DDR2 running alongside 2 x 1GB sticks of Corsair 6400 DDR2, and they're working fine. Despite this though, I would say it's better to buy 8500 as there may be conflicts mixing RAM modules with different speeds.
 
bazmo said:
cool, thanks for the help guys. I'll get some ordered and have a go at bumping it all up to 1066 too :)
Click to expand...

check your setting if i am correct your memory is running at 400mhz x*2 = 800mhz, what you need to do is up your memory fsb to 533 (533*2=1066mhz), and adjust your voltage and rating to what is stated on the memory, i dont know about corsair but as you can see i only run OCZ and i never had a problem.

Your will also see a bit of speed increase too since your cpu FSB is set at 1333 by default which is 333*8.5=2.83,

I would recommend you using these settings

q9550 having a 1333mhz FSB (1333/4 = 333; 333 x 2 = 667)

give it a go and get back to us, also when you use 4 memorys it get a bit tricky with the memory controller....ie stress but it is a try and error to get things perfect.
 
bazmo said:
  • Intel® Core™2 Quad Q9550
  • Asus P5Q-E
  • 4gigs corsair dominator 8500 DDR2 (2x2gig sticks)
  • I'm running the RAM at 800mhz (not 1066)
  • The only reason I'm not running at 1066 is because the bios defaults to 800 and I didn't want to mess around with the voltages and stuff
Click to expand...

Hey bazmo,

I will have to report you to the Moderators if you don't roll up your sleeves and get some clocking/tweaking done! :D . . . I would suggest you go into BIOS and change the memory from DDR2-800 to DDR2-1066 right away . . . no sweat at all mate! . . . download Memtest86+ V4.10 and burn a bootable CD-ROM to give the sticks a nice testing . . . . once you happy that everything will work fine (it will) proceed to step #2 . . . change the FSB from 333MHz-FSB to 400MHz-FSB and reselect the memory frequency to DDR2-1066, save & exit! . . . there is a slim chance you may have to add some vCore with the chip at 3.4GHz but pretty sure [Auto] will take care of it! :)

  1. Intel® Core™2 Quad Q9550 (8.5x333) 2.83GHz DDR2-1066 [8:5]
  2. Intel® Core™2 Quad Q9550 (8.5x400) 3.40GHz DDR2-1066 [4:3]
  3. Intel® Core™2 Quad Q9550 (8.5x450) 3.82GHz DDR2-1080 [6:5]
Once your happy with step #1 and step #2 and you have run the system in for a few days your ready for step #3 if you have decent cooling and are happy adjusting a few BIOS settings! :cool:
 
haha ok.. ok..

I turned the clocks up on the RAM to 1066, and changed the voltage to 2.1 (this is what the RAM is rated at).

Do I need to change the timings, or should that all take care of itself? According to cpu-z its at 5-5-5-18. Everything appears stable so far.

I'm not really bothered about overclocking the cpu as its the RAM thats slowing me down - basically I want to be able to run a compiler faster. Or will upping the FSB allow the RAM to go faster? As you can probably tell my knowledge is rather patchy on these things! :)
 
bazmo said:
I turned the clocks up on the RAM to 1066, and changed the voltage to 2.1 (this is what the RAM is rated at).

Do I need to change the timings, or should that all take care of itself? According to cpu-z its at 5-5-5-18. Everything appears stable so far.
Click to expand...
Nice one bazmo! :)

The Corsair Dominator DDR2-1066 will normally arrange their timings just fine, if your sticks are now running at DDR2-1066 5-5-5-18 and they pass a few loops of memtest then all is fine . . . I had two sets of that memory and even though both of them said 2.1v on the stickers I didn't have to adjust the voltage manually . . . I gave both sets a good testing and they worked fine @ DDR2-1066 with 1.8vDimm . . . although they may have been slightly better sticks as I have read some do in fact need the full 2.1vDimm . . . anyway yours look fine for the moment! ;)

bazmo said:
I'm not really bothered about overclocking the cpu as its the RAM thats slowing me down - basically I want to be able to run a compiler faster.
Click to expand...

You should put an hour or two aside to do some overclocking . . . you got some nice kit there and it really shouldn't be much effort to achieve this clock (step #2) above:

  • Intel® Core™2 Quad Q9550 (8.5x400) 3.40GHz DDR2-1066 [4:3]
That is a 20% increase in processing frequency and 20% increase in FSB/Bus Bandwidth . . . along with your uBer Corsair Dominator DDR2-1066 that will "fly" and your compiling will compete quicker! :D

Heres the really simple BIOS settings you would need to change, you will probably be fine 3.4GHz using [Auto] vCore . . . what cooler do you have on the CPU?

  • Ai Overclock [MANUAL]
  • FSB Frequency [400]
  • DRAM Frequency [DDR2-1066]
  • Load-Line Calibration [Enabled]

 
cooler on the cpu is a noctua nh-u12p so I should be able to get a decent overclock i'd imagine.

When I put the PC together a couple of years ago I always intended to overclock at some point but never really had a reason to do so until now!

I'll give all this a go at the weekend I think - thanks for all the advice much appreciated :)
 
No probs bazmo :)

All the parameters included for your Intel® Core™2 Quad Q9550 3.4GHz overclock are "stock" with the exception of the processor . . . the 400MHz-FSB and Memory @ DDR2-1066 are both standard issue so you will only really need to pay attention to the processor which obviously will be made to work harder . . . take careful note of "stock" idle/load temps using HWMonitor and also note the "stock" idle/load vCore using CPU-z before you start . . . .

When you dial-up the processor to 3.4GHz you will observe changes in both the idle/load temps & vCore . . . the only real adjustment you may need to make is to vCore if the [Auto] setting doesn't give the overclocked processor enough juice . . . you will be able to find this out by loading up Prime95 (linked above) and running Torture-Test >>> Small FFTs and leaving that to run for a hour or two . . . . if it fails post back and we can take the vCore from [Auto] and manually configure it to feed the beast! :cool:
 
right i'm stuck again... my new RAM has finally arrived, but I can't get it running at 1066.

When I start up the computer with the BIOS setings RAM at 2.1v and 1066, I just get a message at the post saying 'overclock failed'.

Turning everything back to auto fixes the problem.

I've got a few questions....

Just to be clear I've got 2x2gig corsair dominator 8500, and 2x2gig OCZ 8500. Both are rated as needing 2.1 volts.

1) does it matter which slots I put which RAM in? At the moment I've got the corsair in 1 and 2. Is it better to have one set in 1 and 3 and the other in 2 and 4?

2) The corsair timings say 5-5-5-15 (on the actual stick of RAM), whereas the OCZ says 5-6-6-18... what shall I set it to? (i don't even really understand what these numbers mean!)

3) is it safe/necesarry to bump the voltages up higher than 2.1?

Many thanks again for any help :)
 
Hi bazmo,

On the Intel® LGA775 platform the sticks normally in odd banks like so

  1. Corsair DDR2-1066 5-5-5-15
  2. OCZ DDR2-1066 5-6-6-18
  3. Corsair DDR2-1066 5-5-5-15
  4. OCZ DDR2-1066 5-6-6-18
When you use two different types of memory each with their own [SPD] settings the mobo sometimes gets confused? . . . depending what slots you fitted the sticks the board may be reading the Corsair 5-5-5-15 [SPD] info and setting that for all the sticks? . . . in which case the OCZ would be running out of spec?

I think the board "may" read the [SPD] info from whatever stick is in slot #1 (nearest to the CPU) . . . maybe worth fitting testing this out by fitting the OCZ sticks in 1+3 and the Corsair in 2+4 and see if that helps . . .

  1. OCZ DDR2-1066 5-6-6-18
  2. Corsair DDR2-1066 5-5-5-15
  3. OCZ DDR2-1066 5-6-6-18
  4. Corsair DDR2-1066 5-5-5-15
if that doesn't help the board Auto-slacken the timings for all sticks then you will have to manuall set them in BIOS!
 
You can run it fine as long as your motherboard supports it, however you'll be only able to run them both at the maximum speed and lowest timings of the slower stick, hence if you plan on keeping that, then might just as well buy the cheaper lower spec one.
 
ok tried the sticks in a few different combinations of which RAM is in which slot, always with the same result - 5-5-5-18. At the moment I've got them with the OCZ in 1+3, and everything in the BIOS is set to auto.

I did try putting the speed up to 1066 and everything seemed stable for about 2 hours, at which point I got BSOD and the PC wouldn't even post for about 5 minutes after that. Being a complete wuss this scared me quite significantly so I've set it all back to auto :).

Is it safe to run the RAM as it is now, at 5-5-5-18 but at 800Mhz. As in, can the timings be tighter if the clock speed is lower?

Cheers!
 
Hey bazmo,

good effort there! . . . I would have thought the board would have read both sets of [SPD] info and set the slacker 5-6-6-18 timings for both sticks but it didn't seem to work out like that! :D

I'd be tempted to take out the Corsair and test the new OCZ memory by itself just to see if the board set the correct timings and also to make sure the sticks are running error free? . . . I know its brand new memory but its good practice to thoroughly test new hardware within the 7 day no quibble return period for peace of mind . . .

apart from isolated testing . . . I think what you should try next is to manually set the timings in the BIOS to 5-6-6-18 . . . that way the OCZ sticks will be running in spec and everything should be tickety boo! :)

You could just give up and leave all the sticks running "Underclocked" and with slack timings but I think it would be worth the effort to manually configure the memory correctly to unlock the extra performance . . .

  • DDR2-800 CAS5 12.5ns 6,400 MB/s
  • DDR2-1066 CAS5 9.4ns 8,528 MB/s
looking at the figures above thats an extra +33% Memory Bandwidth & -25% Memory Latency you would get by running at DDR2-1066 CL5. . . these are worthwhile gains so don't give up just quite yet! ;)

Once you figured out how to manually set the timings in the BIOS to 5-6-6-18 I would recommend you download Memtest86+ V4.10 (bootable CD-ROM or USB version) and let that run for as many hours as you can . . . if there is any problem with the memory then Memtest86+ will let you know . . . :cool:
 
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