How to get better latency

[ehume]

I have some GSkill F3-16000CL9D4GBRH memory. It will run at 2000MHz but my board will only work with 1066MHz, 1333MHz or 2200MHz.

I would like to reduce the latency and timing of the memory. I don't intent to overclock the CPU, since with Turbo-Boost it overclocks itself.

CPU-Z tells me that at 1333MHz I will have 9-9-9-24 and at 2000MHz 9-9-9-28. It gives JEDEC timings of 8-8-8-22 at 1184 and 7-7-7-19 at 1036MHz. The memory voltage is running 1.5V now, but is designed for 1.65V at 2000MHz.

I have a Gigabyte GA-P55M-UD2 MB with a BIOS that will allow me to adjust most or all of the settings. My questions:

Should I simply try dropping the latency and the other numbers? Should I nudge the voltage up when I do?

Thanks

Ed

[Tradesman]

You can drop the speed and tighten the timings, you'll just want to do it manually. What CPU are you running and I'll have a better idea of your options

[ehume]

Core i7 860. 8GB Ripsaw.

[Tradesman]

Might try setting RAM using stock settings and DRAM voltage, set speed to 1600, command rate to 2T and tRFC to 88 (or 195ish if shown in NS - nano-seconds. See if it boots, if it does you could then try tightening the timings starting with maybe CL8 8-8-8-24 (leaving the other settings as is.

[ehume]

While I was waiting, I eased down some settings. I moved the clock down to 1066, with 7-7-7-22 timings. The tRFC came to 60.

Then I bumped up the voltage and the mem speed to 1366, with 7-7-7-22. The tRFC rose to 74.

I then dropped the timings, 6-7-7-19, 6-6-7-19, 6-6-6-19. The tRFC is still 74. On the last setting I set the voltage to 1.6V. The Windows Experience test runs without causing a BSOD.

The interesting thing is that with the 9-9-9-24 setting, the Windows Experience memory test rated 7.4. My first adjustment -- 8-8-8-22 at 1.5V and 1066MHz -- gave a WE result of 7.5. It hasn't budged since then.

Does increasing the voltage make lower timings more possible?

[ehume]

BTW - here is the CPU-Z validation link.

[Tradesman]

Glad to see your post, many people won't believe that you can get better performance by using slower speeds but tighter timings, but a number of builders and gamers have been doing it for some time now. It can really show up if you get something like 2000 DDR3 and run it at 1600 or 1333 and really tighten down the numbers, it may be a bit more expensive.....but when and if your upgrade, you can move the RAM to a newer mobo and run it at it's rated speed.

And yes, a little extra juice gives you more room to play, with most RAM you generally have at Least oanother tenth of a volt to play with easily and generally .15 so sticks that are rated for 1.6 you can normally take up to 1.7 or even 1.75 - sad part is that very little RAM available or mobos have temp sensors for RAM....what you can do though is check temps of the CPU and mobo and while playing look for rises in the CPU/system temps.

[ehume]

I set the bus multiplier to 12, which gave the 1600 speed. I let the MB decide the voltage and the tRFC, which it set to a little over 1.6V and 88. WE-RAM = 7.5.

When I reduced the timings to 8-8-8-24, I got 8-8-8-29, with tRFC=88 when I booted up. WE-RAM still = 7.5.

[ehume]

Ah, I missed your message. Since I do have the DDR3 2000 RAM, I certainly do intend to tighten down the timing. And I am glad to know that increasing the voltage helps that. It's the crucial information I needed.

My MB says it does not support 1600 RAM speed, but it is doing so. OTOH, when I tried to push it to 2000MHz, it wouldn't boot. It recovered gracefully, though, so I didn't have to locate the reset button.

I guess I need to play around with various settings to see what gives a better result. I will push down at 1600 for a while, then I'll try at 1333 and then at 1066.

I wonder at the effect of letting the MB set the tRAS setting. Does a tRAS of 29 work more slowly than a tRAS of 24? Will it subvert performance, or will it allow the RAM to achieve its potential?

[RamJam]

could give 7-8-8-29 a shot

[ehume]

Right now I'm at 7-7-7-29. It is OK so far. WE-RAM = 7.5

[ehume]

7-7-7-29 worked fine. 6-7-7-29 with auto voltage did not even start booting Win7.

6-7-7-29 with voltage manually set to 1.66 (that makes it 1.65 on this MB) resulted in the OS starting to load, but then it aborted.

I think I have found the limit of the 1600 speed setting.

[ehume]

At speed = 1066, 6-6-6-auto gives me 6-6-6-20 with tRFC = 60.

[Tradesman]

Works..have you benched it to see if any increase in specs....if No, could go back to CL7 and maybe try 7-6-6-29 or maybe 28

[ehume]

Hmm. Thanks for the suggestion. 6-6-6-20 gives no improvement in the score, crude as that score is. Maybe I'll try a 5.

BTW - what does CL& mean?

Thanks.