What's the better quad?

[CRGreathouse]

I was considering a new system (I'm having problems with my current one) and started comparing prices online. I'm looking at two different systems for almost the same price (the Intel one is $15 more) and I wanted advice on which is better. I'll be using the computer primarily for processor-heavy computation, so clock speed, cache, and speed of basic ops (esp. integer division with remainder) are important to me.

Both are quad-core processors with cheap motherboards. The AMD one has better numbers, but I don't know much about their actual relative performance.

Phenom 9950 (2.6 GHz, 2000 MHz bus) w/ ASRock ALIVENF6P-VSTA GeForce 6150SE
Core 2 Quad Q6600 (2.4 GHz, 1066 MHz) w/ PC CHIPS P55G (V1.0)

Any suggestions? I'd also consider suggestions like "get a cheaper processor with a better motherboard" if that would be a better idea.

[petrw1]

Are there stats yet for these two PCs at the Benchmark page?

You would have to dig but I recall reading posts on other forums suggesting that Intel tends to be faster for LL/DC but AMD tends to be faster for TF ... though there are bound to be lots of exceptions as hardware changes.

[Batalov]

In the order of increasing subjectivity:
0. Consider building, not buying a box. If you go with the cheapest box (or assembled for you at an equivalent of Costco) - ...sigh... read on.
1. You need to put the memory in the equation. I'd strongly recommend to use at least DDR2/1066. It's hard to start talking about performance before you spec your memory.
2. I'm sorry but both these motherboards look too cheap and not award-winning or anything. You may want to go with a ~$100 board. You will have spent on electricity more than the difference in price (say, $50) within several months.
3. If you go cheap on motherboard and the memory, then the question will be similar to "what's better -- a Lada or a Yugo?" Sorry! I don't know the answer. Not that I am driving a Porsche, either. You know, "Fast. Cheap. Good. Choose any two." Please don't choose too cheap. Or too fast.
4. CPUs are OK. No "get a cheaper processor with a better motherboard" advice from me. If anything, go to more expensive CPUs, as well. I don't know, a Q9550. Q6600 that I got 13 months ago was brilliant. It is still great. But in 2009?
5. If you are going to do Prime95, then Intel beats AMD; if you want to do factoring (and I don't mean trial factoring), then AMD is better (imho).

Please keep in mind that these are just one man's opionions and you can read and forget them. Your mileage may vary greatly.

Good luck!

[henryzz]

Originally Posted by fivemack

Yes, the athlon64 split SSE2 operations into two chunks done in sequence, whilst the core2 and phenom do the whole operation in a single chunk. So a 7550, which is basically half a Phenom, should have reasonable performance.

Though I suspect the price/performance will be significantly better if you use a 'Phenom II' (45nm quad-core) when they come out - the CPU costs about twice as much as the dual-core, but you don't have to have a second case, motherboard and memory.

[CRGreathouse]

I'm looking to replace an existing computer with a stopgap that will last me a few years. I'm not quite budgeted for the system I'd like, and that's fine with me: I'd like to let the dust (and prices) settle around the i7, 64-bit programming, and multicore support before jumping in with two feet.

I'd consider getting a dual core like the system I'm replacing, but quad cores are so cheap these days...

Originally Posted by Batalov

In the order of increasing subjectivity:
0. Consider building, not buying a box. If you go with the cheapest box (or assembled for you at an equivalent of Costco) - ...sigh... read on.

Of course my question isn't answered by building my own system, as I'll have to make this and other choices if I do. I may assemble but I'm more likely to buy. At the moment I don't see much or any price difference -- but I'll take the final system I decide on and compare newegg component prices vs. assembled cost.

Originally Posted by Batalov

1. You need to put the memory in the equation. I'd strongly recommend to use at least DDR2/1066. It's hard to start talking about performance before you spec your memory.

I've been considering 4 GB of 800 or 1066 MHz DDR2 memory. Would you recommend swapping that for 2 GB of 1066 MHz DDR2 and put the difference into the motherboard?

The calculations that I do mostly tax the cache rather than the main memory (no video rendering or the like), but the speed difference may still matter.

Originally Posted by Batalov

3. If you go cheap on motherboard and the memory, then the question will be similar to "what's better -- a Lada or a Yugo?" Sorry! I don't know the answer. Not that I am driving a Porsche, either. You know, "Fast. Cheap. Good. Choose any two." Please don't choose too cheap. Or too fast.

Well, I want to build/buy a cheap system -- a good machine will have to wait, and anything I get will be an improvement on my Core Duo T2400 (which has serious problems with its hard drive and laptop screen).

Originally Posted by Batalov

4. CPUs are OK. No "get a cheaper processor with a better motherboard" advice from me. If anything, go to more expensive CPUs, as well. I don't know, a Q9550. Q6600 that I got 13 months ago was brilliant. It is still great. But in 2009?

Hopefully this will only need to last for 2-3 years instead of 4-6.

Originally Posted by Batalov

Please keep in mind that these are just one man's opionions and you can read and forget them. Your mileage may vary greatly.

I appreciate your time and expertise.

[lavalamp]

How much are you looking to spend? A build-your-own i7 920 system with 3 GB of RAM may be within the realm of possibility.

Example core system:
i7 920 - $294.99
Gigabyte UD3R - $209.99
Crucial 3*1GB - $73.99

Of course, you still need a case, PSU, HDD, optical drive, and graphics card, but the above are the core componants for $578.97. Including the rest of the stuff I just listed, a full system could come to less than $700.

[CRGreathouse]

Originally Posted by lavalamp

How much are you looking to spend?
[...]
Including the rest of the stuff I just listed, a full system could come to less than $700.

I was looking to spend less than that, but I must admit it's compelling. Maybe I'll just try to keep my system running for a while longer and then go for it. I didn't know the i7 was so cheap!

[Batalov]

Oh, I was just about to say, if you would reuse the HDD, the case and the monitor, then $700 would be within reach. That's a nice system core above, and enviable too. Gigabyte makes good boards.
The grocery bill paradox will probably get you a bit over - with all the little things. There's also the cooler option (under full load the cheap fans Intel throws in the box will show weakness, come summer - see the "is 70C normal temperature?" threads; but you can add that later, even a good one is ~$50). There's also a mini-fan for the bridge (did they start to put them on the mobo? I'll look.)

If you would stay with the OP choices and DDR2 - I'd say get less of faster, because you will be able to add later. If you do 800, then you'll stay with 800. I think the 800 memory is the reason of the "duo is better than the quad" threads, where they say that 4 cores work for 2.5 cores (while a duo works for 1.9x). I see 3.3x productivity from 4 cores on the 4x LL test (that's for a reference, if this is similar to your jobs; I do other stuff for which it has a full 4x performance).

P.S. The warehouse (Costco, Fry's, etc) cheapest boxes are, unfortunately, their way of getting rid of the weakest memory - last year AFAIR it was 533 at best, not even 800. I was thinking like you are thinking, until I raided all the stores (online and physical). Then I built the box - my first in the decade. And it wasn't all that painful. I was in luck that Q6600 was excellent then and right after a half-price drop and I've risked with the 1066s which were in very limited choice. Could have flopped, but I lucked out.

[Uncwilly]

This one?

[CRGreathouse]

Originally Posted by Batalov

Oh, I was just about to say, if you would reuse the HDD, the case and the monitor, then $700 would be within reach.

I have none of these. My laptop's hard drive is failing, and this is the reason I'm looking at a new computer.

Originally Posted by Batalov

If you would stay with the OP choices and DDR2 - I'd say get less of faster, because you will be able to add later. If you do 800, then you'll stay with 800. I think the 800 memory is the reason of the "duo is better than the quad" threads, where they say that 4 cores work for 2.5 cores (while a duo works for 1.9x). I see 3.3x productivity from 4 cores on the 4x LL test (that's for a reference, if this is similar to your jobs; I do other stuff for which it has a full 4x performance).

OK, I'll keep that in mind.

[lavalamp]

Earlier I said a system for $700, after looking at a breakdown of individual components, I believe $750 is nearer the mark, not including monitor/keyboard/mouse.

Also bear in mind the added benefit of HyperThreading for the i7s. It may not help at all with LL tests, but for sieving, the performance increase is substantial. On a fairly large sieve using sr1sieve I've found that running two sieves on a single core gains me a 25% speed bump.

In particular the sieve ran at 8 million p/s, and running two sieves on a core gets me 5 million p/s each for a combined 10 million p/s. This was a sieve with over 375 thousand candidates, spanning an n range of almost 8 million, and running on a 4.2 GHz i7.

Warning - long overclocking post follows.

With a good aftermarket cooler for the CPU, 3.5 GHz should be easily attainable. The stock cooler is only good for stock frequencies, much more and temps get high pretty quickly. As an example, I used a 920 (2.66GHz) stock cooler on a 965 (3.2 GHz) in a VERY well ventilated case in a cold room, and while encoding video with x264 the 965 hit 100 C.

If you were to attempt overclocking I would recommend using at least 1333 MHz RAM. Then something like the following would be a nice clock:

CPU 175*20 = 3500 MHz
Uncore 175*16 = 2800 MHz (the uncore includes the L3 cache, the faster this is in relation to CPU speed, the lower your cache latency is)
Mem 175*8 = 1400 MHz
QPI 175*36 = 6300 MHz (stock for i7 965 is 133*48 = 6400, usually tops out at around 8000, your mileage may vary)

If you wanted to try for an even higher overclock, the memory multiplier would need to drop down to 6 and you would lose some performance there. So if you want to push harder, lay down for even higher frequency RAM (this is similar to the stuff I have in mine and I've run it as high as 1700 MHz and 1.68 V without having to change the latencies).

CPU 200*20 = 4000 MHz
Uncore 200*16 = 3200 MHz
Mem 200*8 = 1600 MHz
QPI 200*36 = 7200 MHz

Alternatively with the slower RAM:

CPU 211*19 = 4009 MHz
Uncore 211*16 = 3376 MHz (now in a better 19:16 ratio with CPU, was 5:4 before)
Mem 211*6 = 1266 MHz
QPI 211*36 = 7596 MHz

Alternatively alternatively with the faster RAM:

CPU 211*19 = 4009 MHz
Uncore 211*16 = 3376 MHz
Mem 211*8 = 1688 MHz (around this frequency and at 8-8-8-24, the memory latency is just less than 29 ns according to Everest)
QPI 211*36 = 7596 MHz

So long as you have a well ventilated case with tidy cables, these clocks should be within reach of an air cooled system and be Prime95 stable. Clocks this high, and higher, on air frequently pop up on overclocking forums.

If I had known that the i7 CPUs overclocked this well before I bought one, I would have bought a 920 instead of a 965, and I would have gone with air cooling rather than water.

With the Noctua cooler and OCZ 1600 MHz RAM I linked to, plus a few other improvements to make it more overclocker friendly, the total system cost is pushed towards $900. Plus anything else you may need such as monitor/keyboard/mouse.

I've attached a list of components which could make a very nice little system. It's not the cheapest it could possibly be, some parts could be removed and others could be swapped for cheaper variants, but as it stands it would make quite an excellent overclocked cruncher, and for a shade under $900. Since you said you were looking to spend less than $700, this number probably won't be too welcome, so sorry about that, you'll have to have a word with Intel and Gigabyte.