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Memory Benchmark puzzling me

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June 24, 2007 8:46:50 AM

Hi

I have ust built a new PC built based on a P35 chipset motherboard. It all went pretty smoothly but I am puzzled about how it benchmarks against my older PC. I was expecting it to be markedly faster on memory bandwidth than it is. I am probably misunderstanding something, maybe someone here can explain what is going on ? The Specs below.

OLD PC
Prescott P4 3.5 GHz
FSB 200 MHz
Ratio FSB:D RAM 3:4 Giving Ram Freq= 266.7 Mhz (from CPUZ)
Setting 4-4-4-10
measured read speed = 6,074 Mbytes/s (Everest)
RAM Bandwidth = 4,536 Mbytes/s (Sisoft)


New PC
Core 2 Duo 2140 Overclocked to 2.2 GHz
FSB 275 MHz
Ratio FSB:D RAM 1:2 Giving Ram Freq= 550 Mhz (from CPUZ)
Setting 5-5-5-15

measured read speed = 6,938 Mbytes/s (Everest)
RAM Bandwidth = 5,626 Mbytes/s (Sisoft)

Both PC's running 2 DDR2 sticks, DUAL interleaved.

As the RAM frequency has doubled shouldnt that be much more significant than the slightly slower memory timings of 5-5-5-15 ?

Thanks for any ideas

Regards Geoff
June 24, 2007 9:33:31 AM

Did you know that theres isn't a huge difference between DDR2 800 & DDR2 1250MHz. There are some difference's: DDR2 1250MHz overcomes the high latencies with more MHz. Its a MHz to latency balance. Some people like running DDR2 800Mhz @3-3-3-8, or 5-5-5-15 @1250Mhz. The real fact is for gaming high Mhz is better as games like Mhz more. I just upgraded from DDR2 533Mhz to DDR2 1200Mhz and saw a huge diff. Try tightening up your timings a little and I bet you score higher. DDR2 1250Mhz starts to show some incredible memory speeds passed 400 FSB.
June 24, 2007 11:02:59 AM

Hi

Thanks for the response

I wasnt expecting to see a doubling of benchmark even though I doubled the clock to my RAM, but I was expecting better results than I am seeing. The latency and 5-5-15 timing must have way more impact than I guessed.

These memory spec. figures get confusing, you quoted you had gone from 533 Mhz to 1200 Mhz. These cant be the raw input frequencies ? You are quoting after doubling the real frequency due to the 2 transfers per clock I think ?

If I quote my figures in the same way that means I have gone from effective 533 Mhz to 1100Mhz. Just trying to get these figures clear in my head.

Incidentally, my new memory is Crucial Ballistix, seems good so far, I should be able to push it a bit harder yet but havent tried till I figure out what overclock my new cheapo CPU can handle

Regards Geoff
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June 24, 2007 12:09:33 PM

Quote:
Hi

Thanks for the response

I wasnt expecting to see a doubling of benchmark even though I doubled the clock to my RAM, but I was expecting better results than I am seeing. The latency and 5-5-15 timing must have way more impact than I guessed.

These memory spec. figures get confusing, you quoted you had gone from 533 Mhz to 1200 Mhz. These cant be the raw input frequencies ? You are quoting after doubling the real frequency due to the 2 transfers per clock I think ?

If I quote my figures in the same way that means I have gone from effective 533 Mhz to 1100Mhz. Just trying to get these figures clear in my head.

Incidentally, my new memory is Crucial Ballistix, seems good so far, I should be able to push it a bit harder yet but havent tried till I figure out what overclock my new cheapo CPU can handle

Regards Geoff


I meant from 533Mhz effective to 1200Mhz (each dimm @600Mhz) effective, these Ballistix's can do 1200Mhz on only 2.25 volts. Higher bin micron memory chips like these can do a lot with little voltage. Get the Ram Fan from CoolIt at NewEgg, your dimms will thank you for it by prolonging the life of these great chips.
June 24, 2007 11:38:36 PM

GW, on current Intel systems, all data to/from RAM has to go through the FSB to/from the northbridge (which controls the memory bus). Thus, the FSB normally bottlenecks transfers to/from RAM, assuming you are running in dual-channel mode.
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