Sign in with
Sign up | Sign in
Your question

Can someone give me a memory timings for dummies lesson?

Last response: in Memory
Share
December 3, 2006 2:40:26 PM

I have some old PC2700 (DDR 400) and I was wanting to make sure that I have it set up correctly. Problem is that I really don't know what I am looking at with the timings etc.

For example, it is DDR 400 but CPUz shows it as only running at 183mhz. Is that normal?

Anyways, I would appreciate any help you can give. I just would like to know what to look at, what I should have it set at, what it means etc....


Thanks
December 3, 2006 2:55:03 PM

PC2700 isn't DDR-400......PC3200 is ;)  So 200mhz x 2 = 400 with PC3200. But since yours is 2700, 183 x 2 = 366, so it's correct. CPU-Z is right. You're simply mistaken in your assumption, no big deal man.

As for what to set it at, it depends what brand it is, and what timings it is rated for. For example, is it 3-3-3-8? Or 2.5-3-3-3-7? Or 2-3-3-6? etc.......

Find out that info and then someone can help. Although, would also help to know what mobo, just in case.



Info for your 2700/3200:
http://en.wikipedia.org/wiki/DDR_SDRAM

Info for your RAM timings:
http://en.wikipedia.org/wiki/CAS_Latency

There's more out there, but it gets REALLY technical. Suffice it to say that, generally speaking, lower RAM timings are better. But that means the RAM is better and has to be able to perform at those faster timings. Not all RAM is created equal....just like cars ;)  The best DDR RAM runs around 2-3-3-5 @ 1T.
December 3, 2006 3:22:21 PM

So it is 2.5-3-3-3-7 2T in CpuZ. It is also running at 181.4 MHZ. Per the corsair memory scanner it is DDR400 PC 3200, not PC 2700. My bad, it is late and I am mixing up builds.

Lol, I just saw that CPUZ had this info as well. It is Kingston P/N=K. Correction=none, unregistered, unbuffered, not EPP.
Related resources
December 3, 2006 3:42:52 PM

I thought DDR PC3200 ran at 333MHz, not 366MHz. I could be wrong...
Anonymous
a b } Memory
December 3, 2006 3:57:58 PM

Mhz * 8 = PC rating
400 * 8 = Pc3200

For the OP:
Look at the sickie up there, full of valuable info.
Also toms hardware had an article back in the days can't seam to look it up =|
December 3, 2006 6:23:22 PM

Unless he has it OC'd. Sounds like his info is a bit mixed up though, so hard to tell what is what.
December 4, 2006 1:26:25 AM

Quote:
I thought DDR PC3200 ran at 333MHz, not 366MHz. I could be wrong...


Doh! :oops:  I meant to say PC2700...
December 4, 2006 3:45:02 AM

Quote:
Unless he has it OC'd. Sounds like his info is a bit mixed up though, so hard to tell what is what.


I did an OC through the bios on my ASrock board. I overclocked my CPU freq from 266 to 290. I am not sure how that OC affected my memory.
December 4, 2006 4:08:23 AM

That will increase your memory frequency. That makes sense now.
December 4, 2006 4:17:12 AM

If that was the case, shouldn't it be reading over 200 instead of 181? I read the FAQ but it is still a bit fuzzy to me. DDR400 should be at approx 200mhz right?
December 4, 2006 4:34:03 AM

DDR 400 (PC3200) runs at 200MHz external clock if your processor is running that fast an external clock too. Your mobo, processor and ram all have maximum rated FSB's and the lowest of these is what you can actually run at synchronously without overclocking.

For example despite my DDR400 ram, my Athlon XP 2800+ runs at 166MHz external x 12.5 multiplier so my ram naturally follows suit at 166 (333MHz DDR). I can set the ram to 400MHz in the BIOS since it supports that & so does the mobo, but this is asynchronous with the FSB and actually makes the comp slightly slower in my tests.

The asynchronous bit means that instead of each cycle in the 166MHz passing data from the ram to the cpu (synchronous), the ram goes on a faster ratio (6/5) and provides data for the bus at this off-beat frequency.

Jo
!