Frequently asked questions about memory and storage:

[palladium]

Intel's official specs call for an absolute maximum of 1.875V for VDIMM for the core i7 platform, but I've heard somewhere ( can't remember) VDIMM and QPI voltage should be within .3 or .5V of each other or you'll run into problems. Because the memory controller is integrated into the CPU, you run the risk of frying your (expensive) CPU if you set your VDIMM too high.

You automatically OC your RAM when you OC your CPU ( unless, of course, you have the Extreme chip) because the BCLK affects most if not all clocks in the CPU, which includes the DRAM clock. (On the Extreme chip you can OC the lazy way by just dialing up the multiplier.) Most MB should allow you to adjust the DRAM multiplier if you don't want to push your RAM too hard ( or the other way around).

 

[Denithor]

Actually, you just set your CPU and RAM multipliers independently of each other and they work off the same "base clock" (called blck by most people).

i7 920 @ stock:
BLCK = 133
CPU = 133x20 = 2.66GHz
RAM = 133x6 = 800MHz or 133x8 = 1066MHz

Some motherboards don't list the multipliers as such, rather they list a memory speed (IE DDR3-800 is equal to a 6 multi, DDR3-1066 is 8 multi) and you just have to know how to convert. The i7 965 features additional multis of 10 and 12 (corresponding to "stock" blck speeds of DDR3-1333 and DDR3-1600, respectively).

Now, overclocking. Remember you can adjust the CPU & RAM multis independently.

920 @ 20x150 = 3GHz
RAM @ 6x150 = DDR3-900 or 8x150 = DDR2-1200

920 @ 15x200 = 3GHz
RAM @ 6x200 = DDR3-1200 or 8x200 = DDR3-1600

920 @ 20x200 = 4GHz
RAM @ 6x200 = DDR3-1200 or 8x200 = DDR3-1600

920 @ 18x222 = 4GHz
RAM @ 6x222 = DDR3-1333 or 8x222 = 1776

920 @ 16x250 = 4GHz
RAM @ 6x250 = DDR3-1500 or 8x250 = DDR3-2000

General notes:
-If you want a higher blck just remember to turn down your memory multiplier if your RAM cannot handle the new speed.
-Keep in mind that DDR3-1333 will handle up to a 222blck (on a 6x multi) which will net you up to 4.44GHz on i7 920 with a 20x CPU multiplier.
-There's virtually no impact on system performance from memory speeds/timings and almost no difference between dual and triple channel mode. Much like the AMD A64/X2/X3/X4 chips these processors are simply not bandwidth limited (for the same reason - the IMC optimizes the flow of data from system memory into the large L3 cache efficiently).
-The best value right now in DDR3 is this G.Skill 2x2GB DDR3-1333 CAS9 @ 1.5V kit priced at $80 shipped. Buy one kit for 4GB in dual channel mode, two kits for 8GB in triple/single channel hybrid mode or three kits for 12GB in triple channel mode.

EDIT: Why is our sticky sliding down the page?

 

[zagood]

BTW, thank you for this:

http://www.thetechrepository.com/showthread.php?t=195

I knew that there was more to overclocking ram than simply timings/bandwidth. Using the CAS latency formula I'm using the following settings on my e5200 + 4x1gb DDR2-800 after early tweaking...

10.5 x 333mhz = 3.5ghz @ 1.3v (1.264 actual)
ram 1:1
3-4-4-10 @ 2.1v

According to the formula, CAS3 @ DDR2-667 = 9ns, while CAS4 @ DDR2-800 = 10ns, so figured with the low potential FSB of this chip that's the best way to go.

Again thx.

 

[BlueAcolyte]

Oh hey, no problem. I just updated this today in fact. Although 9 vs 10ns is probably not that noticeable (sorry )

 

[zagood]

Fine, I'll work on it some more. Bully.

-z

 

[BlueAcolyte]

Good luck with that.

 

[zagood]

Yeah, didn't happen. Couldn't get CAS3 at anything over DDR2-667, even DDR2-700 @ 2.3v.

Looks like I'm stuck with -
DDR2-667 (1:1) | 3-4-4-10
or
DDR2-800 (5:4) | 4-4-4-12

I'll just play with the voltages and see which one I can keep stable at a lower voltage. Running either at 2.1v is stable.

FYI:
2x1gb OCZ Plat. Rev. 2 DDR2-800
2x1gb Patriot PDC22G6400LLK DDR2-800
Gigabyte ep45-ud3p / e5200

-z

 

[TheForsaken]

hi all, can some one help, I buyed 2* 1Gb DDR2 800 ram Kingmax but it is running on 351Mhz insted of 400Mhz what coud be the problem?

I have an AMD 64 Athlon x2 4000+ processor Nvidia 8500GT video card and a GigaBite motherboard...

 

[Gillbot]

Originally posted by: zagood
Yeah, didn't happen. Couldn't get CAS3 at anything over DDR2-667, even DDR2-700 @ 2.3v.

Looks like I'm stuck with -
DDR2-667 (1:1) | 3-4-4-10
or
DDR2-800 (5:4) | 4-4-4-12

I'll just play with the voltages and see which one I can keep stable at a lower voltage. Running either at 2.1v is stable.

FYI:
2x1gb OCZ Plat. Rev. 2 DDR2-800
2x1gb Patriot PDC22G6400LLK DDR2-800
Gigabyte ep45-ud3p / e5200

-z

You probably won't see a difference between the two anyway.

 

[BlueAcolyte]

Originally posted by: TheForsaken
hi all, can some one help, I buyed 2* 1Gb DDR2 800 ram Kingmax but it is running on 351Mhz insted of 400Mhz what coud be the problem?

I have an AMD 64 Athlon x2 4000+ processor Nvidia 8500GT video card and a GigaBite motherboard...

Did you have any other RAM? Can you go into the BIOS and tell me some of the values you see?

(HT multiplier, base clock, memory multiplier, etc.)

 

[TheForsaken]

Hi, I can't tell you now anything, I'm working right now, I have other ram 2*512DDR2-800
I swiched it yesterday and it has the same problem now, it shoud also run on 400Mhz bot it doesen't... ant this thing HT multiplier, base clock, memory multiplier, etc. I can't even fied them. but after I get home I will post everithing I can fiend, thx for the responsd.

 

[TheForsaken]

I took a walk around in the Bios but I didnt fiend enithing you asked for,I have a Gigabite GA-M61SME-S2 motherboard.
This is all vhat I can see in bios : Standard CMOS FEATURES
ADVANCED BIOS FEATURES
INTEGRATED PERIPHERALS
POWER MANAGEMENT SETUP
PC HEALTH STATUS
and the usual load save features...

 

[BlueAcolyte]

Hmm, no Motherboard Intelligent Tweaker or something?

 

[imported_Jid]

EDIT: never mind

 

[dedejean]

this thread helped me alot!!! thanks so much.

 

[steveboas]

hi there,

i'm a newbie n i have a one question:
i have a blade server using 1 processor E5430
each blade have 8 slots for memory which is dual channel.

which configuratin is better performance
4 x 4 GB FBD PC2-5300 (2 x 2 GB) Kit populated on all slots (8).
or
2 x 8 GB FBD PC2-5300 (2 x 4 GB) Kit only populated on 4 slots.

thanks before

 

[BlueAcolyte]

There will be little performance difference, but if its not too much more expensive go with 4x4 gb. (half slots filled)

 

[BlueAcolyte]

bump...