[nolonger]

Well I just did some benchmarks and discovered my brother's Kingston crap RAM runs faster at 900MHz 5-5-5-15 than 960MHz 5-5-5-15.

The values I found were:
900MHz 5-5-5-15 1.9V
read: 7009MB/s write: 6341MB/s copy: 6760MB/s latency: 71.3ns
960MHz 5-5-5-15 1.94V
read: 6773MB/s write: 6336MB/s copy: 6719MB/s latency: 77.9ns

This was using Everest benchmark. Am I right about the FSB straps or is this something else?

 

[-n7-]

Your mobo is the Asus Rampage Formula X48?

Then, unlikely.

Way more info needed.

CPU info (multi x FSB was what?)

RAM ratios for the above.

Subtimings info (tRD was @ what?).

 

[ACHILEE5]

OP, what speed is your FSB?

 

[nolonger]

12.5x multiplier, 300MHz FSB
Ram ratios were 16:8 for 900MHz and 16:10 for 960MHz.
All timings were the same, although I gave the RAM an extra 0.04V in between those settings.

 

[-n7-]

Quote:

Originally Posted by nolonger 12.5x multiplier, 300MHz FSB Ram ratios were 16:8 for 900MHz and 16:10 for 960MHz. All timings were the same, although I gave the RAM an extra 0.04V in between those settings.

Wat?

If FSB is 300 + DDR2-900, that's 2:3 ratio, which is on the 266 strap by default.
If FSB is 300 + DDR2-960, that's 5:8, which is 333 strap by default.

Anyway, 266 will apply a tighter tRD (& possibly other subtimings) if it's left on auto, which is precisely why you are getting better scores @ DDR2-900.

You can see tRD (Performance Level) with MemSet.

If you set tRD manually to the same, DDR2-960 will be faster.

 

[nolonger]

I'm sorry, I meant 2:3, not 16:8. Can't give that a try at the moment since the ram sticks are on my brother's computer, but I'll try tomorrow.
Thanks for the response!

 

[Blameless]

FSB straps often set the default tRD. Slower tRD at the faster strap is what's causing the performance discrepancy.

 

[DeadSkull]

Well also higher rate fsb itself allows for higher bandwith.

See http://www.overclock.net/7724692-post1436.html

same memory clocks/timings (except for trfc but it doesnt do much) and even lower cpu speed but because fsb/rated fsb is higher everest bench numbers are also higher across the board for memory.

 

[nolonger]

FSB was left at 300MHz, I didn't change it at all. Too much work for tomorrow so I might not be able to bench these until Tuesday.

 

[guyladouche]

OP, does the mobo offer a selection of the same mem multiplier but using different straps? For example, on my mobo bios, I have a 4.0, 4.0+, and 4.0~ settings--each denominator corresponds to a different strap--800, 1033, and 1333, IIRC. Is there an option for that in your bios? That might be a better indicator of strap effects.

Also, for your RAM, were ALL of the RAM timings/latencies manually set? Sometimes they are hidden in the main memory timing/latencies menu, and some are set to auto, which might also be the cause of the discrepancy.

 

[nolonger]

I had some timings on Auto. For the FSB straps my motherboard sets them automatically based on what ratio I use.

 

[Acoma_Andy]

Quote:

Originally Posted by nolonger I had some timings on Auto. For the FSB straps my motherboard sets them automatically based on what ratio I use.

But you can also set the straps manually, and then select a speed.

 

[nolonger]

Yes, I can. Don't have enough time left today to test this, but Tuesday hopefully.