Turn off SPD: Extra timings? What are they supposed to be!?

Ok so i have a small problem. First, I have this ram:

http://www.memoryexpress.com/Products/PID-MX19639(ME).aspx

Right now SPD is controlling my ram timings, but i want to set them manually. When i turn off SPD i get the normal timings to set, but then there are a bunch of other ones i have no clue what to set them at:

tRC, Dram Idle timer, tRCD, etc. (i took these from a screen shot of CPUID - im at work and cant get the exact names from my bios).


Where do i find the info on the extra timings? I have no clue what to set them at.

The only timings you really need to set are those first 4. (4-4-4-12) It's not necessary to change the sub-timings and you probably wont see a difference even if you did. Unless you're running SuperPi. So you can go ahead and leave them at Auto.

According to that site .. those sticks run at 5-4-4-12 @ 800Mhz .. So run them at that .. Those timings are already pretty tight so you'd be real lucky to improve them ..

Check out the Memory: Basics, Tweaking & Overclocking sticky at the top of this forum.

Ok the extra timings turned to this when i disabled SPD

tRFC: 38
tWR: 12
tWTR: 12
tRRP: 12
tRTP: 12

I'll check over that post that you suggested redduc - although im pretty sure ive been through it all. I dont remember it saying anything about what the extra timings should be at - or even a way to calculate what they should be.

Sizmo said:

Ok the extra timings turned to this when i disabled SPD

tRFC: 38
tWR: 12
tWTR: 12
tRRP: 12
tRTP: 12

Click to expand...

When you disabled SPD and enabled the Manual setting, the timings shown at present will be the current SPD timings...
Using the above sub-timings as an example, higher numbers relate to looser timings. Altering / tightening sub-timing values will normally show only a slight improvement in applications, but will usually show a noticeable improvement in bechmarks like the Sandra "Memory" bench for example (if tightened a significant amount - although that isn't always true, as sometimes even a small change will be noticeable). Altering Performance Level (tRD) on the other hand has a major impact on system-wide performance, and not just benchmarks. So looking at your existing timings, I'd probably change only tRTP to a lower number numerically... around 3 or 4, then run Memtest86+ to check for errors; before attempting to boot into Windows.

I dont remember it saying anything about what the extra timings should be at - or even a way to calculate what they should be.

Click to expand...

When OC'ing RAM, one of the objectives is to obtain the tightest timings at the lowest voltage (Vdimm). This is why changing from SPD to Manual is advantageous, so as to be able to set the timings manually and achieve the best / highest possible memory bandwidth. There is no "what the timings should be", or "a way to calculate what they should be" when OC'ing RAM, as your concern is as I mentioned... setting them to as tight as possible w/ as little voltage as necessary, while at the same time creating a stable system with the highest frequency. You can download v2.01 of Memtest86+ from here...

http://www.memtest.org/

... and start experimenting.

I have to disagree with inkfx about the importance of subtimings. On the one hand he is correct that you won't feel a difference. But by the same token, good luck feeling a change in your main timings. RAM speed and timings has little real world effect on PC performance.

However, I can say that overtight timings can and do cause instability. As I seem to mention in 3/4 of the posts I make, tRFC (generally your highest latency of all) will cause failures in P95 Large-FFT, but will not be caught by Memtest. So if stability matters, don't mess up your subtimings.

Also, I have read that you can see differences in benchmarks by changing subtimings that are as significant as those resulting from changes to main timings. Some matter much more than others though, and I don't remember which are the important ones.

Two very useful tools for determining what you RAM timings are being set to automatically are MemSet and SPDtool. Odds are that your 12-12-12-12 subtimings are not actually what are being set by SPD, but rather just the default starting point in manual mode. My old P5B Deluxe was 10-10-10-10, but Memset revealed that to not be the numbers it used in SPD mode. Also that was too tight for stability on 2 of those timings.

Boot with setting on SPD/Auto, then run MemSet - that will tell you your true timings and give you a great reference point.

You can use SPDtool to see what the RAM is "officially" rated for at a few speeds (usually 266, 333, and 400 for good RAM). Just read one of your modules into the program, and at the bottom of the window there is a tab called "Timings Summary" which will tell you what the actory recommends. However, I think sometimes some of the numbers it gives you can bee too tight, and I think Memtest will give you a better set of number to work from.

Ah thanks for the response Esveezy. I was suspicious of the initial timings when turning off Auto/SPD. Everything just set to their max values as a default. (ie, my 5-4-4-12 ram went to like 6-6-6-18 by default).


Anyway, ive got those 2 programs and im going to play around with them to find a good starting point for those extra timings. right now ive kept them at their 38/12/12/12. We'll see what happens!