Memory Timings, Latency, and Frequency

OmniDyne

OmniDyne

Active Member
Hello!

I have a few questions about the memory in my system. I built this computer in June 2017. I've had no issues at all; no crashes, no hangs. It runs well. I'm curious about the DRAM frequency and timings profile the motherboard has automatically set the memory to.

CPU-Z shows DRAM frequency and timings slightly higher than what G.SKILL recommends. The BIOS (non-UEFI) mimics what CPU-Z reported, so CPU-Z seems to be accurate, and reports settings at JEDEC #6.

G.SKILL recommends CL9-9-9-24, which according to CPU-Z, would be XMP-1600. I didn't see an XMP profile option in the BIOS, and the memory profile is set to Auto.

G.SKILL Ripjaws X Series 8GB (2 x 4GB) 240-Pin DDR3
Motherboard: GA-78LMT-USB3 (rev. 6.0)

All BIOS settings are stock, Auto. No overclock.

CPU-Z reports DRAM frequency at 1607MHz. Is this an issue?

Is a slightly higher latency something to be concerned about at all?

CPU-Z Memory.jpg
 
OmniDyne said:
G.SKILL recommends CL9-9-9-24, which according to CPU-Z, would be XMP-1600. I didn't see an XMP profile option in the BIOS, and the memory profile is set to Auto.
Click to expand...
CPU-Z is reading that profile off the SPD on the RAM
OmniDyne said:
CPU-Z reports DRAM frequency at 1607MHz. Is this an issue?

Is a slightly higher latency something to be concerned about at all?
Click to expand...
No to both. The frequency will jitter a little bit around the configure value. The latency is about the same amount of real time (CAS 11@800MHz = 0.00000001375 seconds, CAS 9@685MHz =~ 0.00000001314 seconds), not worth worrying about.
 
Looks fine, it's polling out of the jedec #6 table.

If you set the xmp profile in bios it will set those lower latency values for you. Typically you just set xmp on and it will apply that table you see in cpu-z
 
Cromewell said:
(CAS 11@800MHz = 0.00000001375 seconds, CAS 9@685MHz =~ 0.00000001314 seconds)
Click to expand...

Awesome, thank you. That's an incredibly small difference ha.

beers said:
If you set the xmp profile in bios it will set those lower latency values for you.
Click to expand...

It doesn't appear this board or bios support XMP, from what I could find. I suppose I'd have to set those values manually, if it were worth it.
 
From the looks of it the board only goes up to 1333MHz automatically, to get any higher than that you'd need to do it manually. Under the SPD tab the timing tables should give you detailed latencies to match the XMP profile, which theoretically should work if you just match them. I did notice some slight gains when tightening up timings on my 8320 system as the auto (also Gigabyte) was all out of whack and gave me terrible timings similar to what you have. Give this a read thru.

https://www.computerforum.com/threads/different-ram-kit-weirdness.238698/
 
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