Memory Scaling on Core i7 - Is DDR3-1066 Really the Best Choice?
by Gary Key on June 24, 2009 9:00 AM EST- Posted in
- Memory
Heavy Multitasking: The Other Safe Haven for Faster Memory
The vast majority of our benchmarks are single task events that utilize anywhere from 23MB up to 1.4GB of memory space during the course of the benchmark. Obviously, this is not enough to fully stress test our 6GB memory configuration. We devised a benchmark that would simulate a typical home workstation and consume as much of the 6GB as possible without crashing the machine.
We start by opening two instances of Internet Explorer 8.0 each with six tabs opened to flash intensive websites followed by Adobe Reader 9.1 with a rather large PDF document open, and iTunes 8 with The Who blaring loudly. We then open two instances of Lightwave 3D 9.6 with our standard animation, Cinema 4D R11 with the benchmark scene, Microsoft Excel and Word 2007 with large documents, and finally Photoshop CS4 with our test image.
Before we start the benchmark process, our idle state memory usage is 4.05GB. Sa-weet!
We wait two minutes for disk activity to cease and then start playing Pinball Wizard via iTunes, start the render scene process in Cinema 4D R11, start a resize of our Photoshop image, and finally the render frame benchmark in Lightwave 3D. Our maximum memory usage during the benchmark is 5.62GB with 100% CPU utilization across all eight threads.
Our idle memory footprint after the benchmark has completed is 5.23GB. Trying to run our normal Photoshop benchmark at this point resulted in an out of memory error and automatic shutdown of Photoshop CS4 x64.
Our results follow an almost linear scale as we increase memory bandwidth in this benchmark. Improved latencies only matter when combined with increased memory bandwidth for the most part except for the DDR3-1333 C6 results just edging past the DDR3-1600 C9 score.
There is an 8% improvement in the total benchmark score when moving from DDR3-1066 C7 to DDR3-1866 C7. If you multitask with several memory intensive applications, at stock CPU speeds, increasing memory bandwidth is a simple way to improve performance.
Overclocked
Based on the above results at stock CPU speeds, we decided it would be interesting to look at what occurs when we overclock the system. We arrived at a 3.8GHz processor clock speed via the 19x200 setting. Essentially this is a free overclock as our CPU only needed an increase in VTT to 1.35V (board/processor dependent) to handle the increased memory loads at DDR3-1600 C6 and DDR3-2000 C8.
It is not until we hit DDR3-2000 C8 that our system responds favorably to increased memory bandwidth. Even then, the improvement is not as drastic as our stock numbers as going from DDR3-1200 C5 to DDR3-2000 C8 only improves performance by 2%.
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Seikent - Wednesday, June 24, 2009 - link
I'm not very sure if it's relevant, but I missed a load times comparation. I know that the bottleneck there should be the hdd, but I still think that there can be a performance boost.deputc26 - Wednesday, June 24, 2009 - link
ave and min lines are mixed up.MadBoris - Wednesday, June 24, 2009 - link
I'll be considering upgrading in October at the same time I go from XP to Win 7.So this is good to know if/when I go Core I7.
I guess I can see how Winrar RAM workload sdtays high since it grabs the buffers of compressed data chunks and writes them to disk as fast as the HW permits, so bandwidth matters then.
While it looks like very few apps can saturate the bandwidth latency benefits/penalties are always having an effect as usual.
Maybe I missed it but I didn't see anywhere in the article that tried to explain the technical reasons "why" 2000 doesn't provide advantage over 1066.
I understand the differences of latency and bandwidth. Is it really because no software is using RAM workloads large enough to benefit from increased bandwidth (except compression) or is there another bottleneck in the subsystem or CPU that doesn't allow moving all the data the RAM is capable of?
vol7ron - Wednesday, June 24, 2009 - link
Your question is long, so i didn't read it all, but does bottom of pg2 answer:"That brings us to another story. We had planned to incorporate a full overclocking section in this article but our DDR3-1866 and DDR3-2000 kits based on the Elpida DJ1108BASE, err Hyper ICs, have been experiencing technical difficulties as of late."
They said some other stuff, but it seems like it wouldn't be right to post info on faulty chips.
TA152H - Wednesday, June 24, 2009 - link
I'd like to see a test between the crippled i5 memory controller with very fast memory, and the i7 with low cost 1333 Mhz memory. There's really no point in the 1066 memory, except for Dell, HP, etc... to throw in generic machines; it's not much cheaper than 1333 MHz, and the performance bump really seems to be biggest there. I think 1333 MHz (low latency) is a reasonable starting point for most people, the cost seems to warrant the performance. After that, you definitely see diminishing returns.It seems anyone buying an i5 with very expensive memory is probably a fool, but, a few benchmarks might be interesting to validate or invalidate that. Of course, the i5 might be better when released, so even then it wouldn't be proof.
Gary Key - Wednesday, June 24, 2009 - link
I wish I could show i5 numbers, but that ability is officially locked down now. I can say that our results today will not be that much different when i5 launches, low latency 1333 or possibly 1600 will satisfy just about everyone. :)strikeback03 - Thursday, June 25, 2009 - link
Of course, by the time you can share those numbers we will most likely have to specify whether we are talking about LGA-1366 i7 or LGA-1156 i7. Thanks Intel.kaoken - Wednesday, June 24, 2009 - link
I think there is a mistake with the farcry graph. The min and avg lines should be switched.hob196 - Thursday, June 25, 2009 - link
Looking closer it might be that you have the SLI min on there instead of the Non SLI min.halcyon - Wednesday, June 24, 2009 - link
It's so nice to see AT calling things as they are.This is why we come here.
Straight up honest talk from adults to adults, with very little marketing speech and numbers do most of the talking.
Excellent test round up, mucho kudos.