Ram timings: JEDEC vs EPP in CPU-Z

[kyeana]

I have a question for someone really quick.

I have 2 gig's of ddr2 800 MHz 4-4-3-5 G. Skill ram. Under CPU-Z there are 3 sections JEDEC #1 JEDEC #2 and EPP. Im Trying to figure out which one of these shows the correct timings of the ram. I know it isn't JEDEC 1 because that one says the ram is only running at 333 MHz and i have manually clocked it to 400 MHz. However both JEDEC 2 and EPP have the ram running at 400 MHz.

The JEDEC 2 has the timings at 5-5-5-15 where the EPP has the timings at the advertised 4-4-3-5. I have the timings on the ram set to auto in the bios because the mobo wont let me manually change the tRAS bellow 9. I am wondering if i am getting the advertised 4-4-3-5 (as EPP says) or if im getting 5-5-5-15 (as the JEDEC says)

Thanks in advance

 

[cmashwin]

Under CpuZ, click on the "memory" tab.. Whatever frequency and timings are given there is the "ONLY" correct one... U r probably looking at the "SPD" tab where the plausible timings for various common frequencies are given.

 

[kyeana]

5-5-5-15 under memory tab... thats too bad. Looks like its time to flash the bios / manually clock it to as tight as i can get it (probably 4-4-4-9)

Thank you

 

[cmashwin]

no need to flash or clear ur CMOS/BIOS... Just tighten ur timings one-by-one to as tight as u can get it.. U can probably get it at ur EPP of 4-4-3-5.. Go for it!

 

[Zorg]

^ Agreed. The SPD tab shows the timings at the various speeds that the manufacturer says are the correct ones for that specific RAM.

 

[Maziar]

I don't think its necessary to lower them to 4-4-4-9 if u want to OC, i think 4-4-4-12 or 4-4-4-15 would fine

Zorg, i have a question,my RAMs default timing is 4-4-4-15(and i haven't changed it) but u said that SPD shows the correct timings for the specific RAM and 4-4-4-15 isn't in the list

 

[Zorg]

Well what's in the list?

They aren't the only timings that can be used, they are the recommended lowest timings. Mobos usually have the default timings set higher to ensure that they boot.

It also doesn't mean that the RAM won't run at tighter timings than what is in the SPD. These timings cover their butts as well. They don't want the SPD so tight that the RAM gets flaky, although I'm sure that they feel the competitive pressure to make them as low as they can, because it looks better on the package.

 

[Maziar]

Well my RAM has 4-4-4-15 timings and the SPD page is like this:

 

[Zorg]

Your FSB is 356 so you are a little higher than 333 and lower than 400. You could try the 4,4,4,13 or 4,4,4,12 and see if it is stable, but to be honest I don't think you will see any real world improvement. Sure the benches will get a little better but that won't carry over with the core 2 arch. I would keep it where it is. It's stable and lowering it won't really help.

 

[Maziar]

Yeah its stable and as u said i dont think moving from 4-4-4-15 to 4-4-4-12 would make a noticeable difference
Thanx for the help

 

[kyeana]

i might just go 4-4-4-12. The reason that i can't lower it to the advertised 4-4-3-5 is that my motherboard wont let me put the tRAS (the 5) manually bellow a 9 (which is why i was considering updating the bios). However i have my cpu running a 20% oc at 3.2 GHz right now, and i will probably push that up to 3.6 in the coming days, so 4-4-4-12 timings should work fine so that i can keep the 1:1 ratio

So im curious, you normally see ram at 5-5-5-15 or 4-4-4-12. Is there some reason why it is more stable that way or could you just as realistically use any numbers and have a stable system (for say 3-7-2-15)?

 

[Zorg]

techPowerUp! :: Memory Timings Explained