Default RAM settings?

[HankB]

(Mods - I'm torn between putting this in the Motherboard and RAM section so feel free to move if I got it wrong.)

I was running Memtest86+ the other day and was surprised to see that the RAM was not running at the speed I expected. First the RAM:



I found it running at:


I went into the BIOS and found that with some tweaking, I could get:



This is on an ASRock Z87M Extreme4 motherboard. I suppose I should have captured the BIOS screen as well (and can do that if it is important.)

I'm wondering why the default values are the way they are and if changing to what is listed above will produce better performance. My recollection is that the default settings resulted in a faster RAM clock so perhaps the latency differences just wash out. The processor is mildly overclocked but I have not messed with the RAM.

Clunk! I just examined the blue screens above and see that the default timings result in 20115 MB/s and the changes I made drop that to 13672 MB/s. That's quite a drop! I guess the next time I'm in the BIOS I'll change it back.

Thanks!

 

[Woomack]

Default ( auto ) settings are probably 1600 11-11-11 for this kit. XMP settings are 1600 9-9-9.

Memtest is not always showing correct memory speed. The same about that memory bandwidth. Also look that 1st screenshot is on single CPU core, 2nd is on all cores+ht.

Check memory performance in windows. Best is to run AIDA64 and compare various settings.

You can probably overclock this memory to 1866 or 2133 keeping low voltage. It should give you couple of GB/s higher bandwidth as Haswell likes higher clocked memory. It won't improve daily performance much but can always play with settings if you have time.

 

[HankB]

Many thanks for the info and suggestions. Unfortunately (or not!) no Windows benchmarks here, but google tells me there are RAM benchmarks for Linux.

I'll take a shot at overclocking it as well. Couple percent here, couple percent there and pretty soon it adds up.

I'll also try to be ready to hit <F2> when memtest starts up to avoid running it in safe mode.