Should we consider RAM content?

[Rob Williams]

Thanks for the URLs and information regarding those applications... some of what those can do is simply amazing. This is one application to catch my eye... seriously cool stuff. I think I'll stick to SPEC, hehe... since the results we'll get from that are still going to be quite good. I do have to wonder just how important PC speed is to people using those applications mentioned above... I have my doubts that anyone benchmarks them.

I agree on the i7-975 vs. 2x W5580. It's too bad it's not easy for you to simply find out if that much processing power could be utilized. If you're rendering a single project, it's doubtful that it will use all 8 cores / 16 threads, but again, it's really hard to say. You'd have to ask people who would know, I guess... including the company itself.

I think since I am a system builder, it is why I OC. I have an old dual Athlon water cooled system that has been OC-ed for .... well for ever. For the past 3 years, since the dual Opteron box, it has been the best darn email & report writing machine ever!

AMD chips from that era were amazing for overclocking. I had a single-core AMD 3200+ at 2.0GHz and had it overclocked to 2.7GHz for three years straight without an issue. I only got rid of it because I upgraded... I was long overdue for a multi-core chip, hehe.

As for the memory issue, I still don't think it's anything you really need to fuss over. A fast kit of memory isn't that expensive anymore, and I truly believe that you're never going to hit the bandwidth that DDR3-1600 7-7-7 would offer. Especially on the Core i7 platform, where the memory bandwidth is between 3x and 4x the previous Intel architecture, and 2x AMD.

http://techgage.com/reviews/intel/i7_975/13.png

 

[Kougar]

Psi, since you were interested in building a Core i7 rig, were there any bench data that you'd specifically wish to see? I know how Opteron's used to be king, but 60ns latency should not be that surprising.

Using Everest and the settings in my sig, I get a consistent 43.8ns latency, FPU Julia of 17863, FPU Mandel of 9552, and FPU SinJulia of 7898. That should give you some ballpark figures, a stock clocked 975 isn't going to be much slower. Interestingly two E5462's (Quadcore 2.8GHz 12MB L2 cache, 45nm Penryn cores) scored 19,545 on the Julia test.

After reading your comments about the type of programs used, it strongly reminded me of the Stars Euler3D program. Here's the site: Euler3d Benchmark

TechReport loves this program and uses it in even their server testing. Because they do a good job describing the benchmark in detail I'll give them a brief mention here where you can see the program in action on the Core i7 975. If you want I'll run it on this system to show what the clockspeed boost would net.

I fully agree with Rob in that the memory isn't going to make much difference at this point. It sounds like these apps are as CPU-dependant as one could get... so sticking to midrange memory for the best price/performance and spending the money saved on a higher clocked CPU would be best. 6GB of CAS 7 1600MHz DDR3 is floating around $70 still, so that's pretty much the best option just now in my opinion.

 

[Rob Williams]

Kougar, the Euler3D application looks good at first glance. Would you say it's something that would prove useful in our content? I can't look too deep into it right now, but I will next time I get a spare chance.

 

[Kougar]

The Euler3D program is pretty good... it is not the full program, but a slice of it the author used to run a basic level generic test case scenario. Still it is entirely CPU bound and scales well, especially on Core i7. It'll take a little work to set up as it's all command line console based, but if you are looking for a program to test CPU's with, then yes I'd recommend it.

 

[Psi*]

I have over looked this thread ...

Maybe a run of Euler3D with changing only the memory speed of an I7 system is possible? Keep the CPU clock, motherboard, memory timings as consistent as possible in other words.

 

[Psi*]

http://techgage.com/reviews/intel/i7_975/13.png

I meant to comment that this link compares memory bandwidth of systems including the affect of the CPU clock rate ... it would seem. I compared the % change of CPU clock and float MB/s between the i7 systems and it does not directly track the CPU clock. I'm looking for the test methodology page ...

Sooooo, I think my question all along has been "have you compared changes in the speed of the memory clock?" And, you probably have a table someplace that I have been seeing & but not reading.

 

[Psi*]

found it ...

http://techgage.com/article/intel_core_i7_-_choosing_the_best_memory_kit/2

 

[Psi*]

but ...

... I plotted some of the data from that article, "Intel Core i7 - Choosing the Best Memory Kit". The attached screen capture from Excel suggests (from the last data point) multi-core performance may benefit from higher clock rates. Only 1 data point to go on here and not to go irrational, but this is begging for higher clocked memory to be tested.

And, I think that this is suggesting that the slower memory bandwidth limits multi-core performance? Depending on what faster memory speeds would show of course.

 

[Rob Williams]

Just to be clear, when I tested memory configurations in that article, the CPU clock was not changed. That's part of the fun of Core i7... the ability to adjust memory speeds without touching the CPU. When that article was posted, we were testing with pretty common kits, but the landscape has changed drastically since then.

That said, we really, really should follow-up to this article, but I'm really strapped for time right now. I'm hoping that things will change in the near-future, because I'm actually rather interested in testing out even more configurations, especially with faster memory. I'd especially like to introduce even more real-world scenarios, to better get an idea of the benefits for the regular consumer.

As for slower memory limiting the multi-core performance, that's a possibility, but I think the real-world implications would be negligible. After all, there were few tests in this article that showed incredible gains when even doubling the frequency.

 

[Psi*]

It is even more difficult to understand the difference between the multi-core values of 40.46 vs 44.13 suggests for what ever real world applications happen to be.

And, now there is a D0 stepping of the i7-975 which somewhere I just read adds a performance boost vs the C0. Technology changes like this obsolete reviews pretty fast.