Dual core only (so far) and lack of on-die memory controller strike me as unexciting for GIMPS; HTPC or general office systems might be attractive depending on cost.
AMD Athlon II/Phenom II look better from price/performance standpoint right now.

Absolutely no reason to go for one of those from a GIMPS perspective. An i5-750 is $199.99 so why would I spend the same money for a dual core?

[quote=ET_;202183]I just bought an i5 750 @ 2.66 GHz. It comes with its Intel cooler.

From what I read in this tthread, it should be safe to run GIMPS 100% with it, as Petrw said...

Luigi[/quote]

I ran the i5 750 for a couple of weeks using the Intel cooler. Running Prime95 full throttle, the chip ran at 77-80C.

Then I installed this Cooler Master cpu fan...
[url]http://www.tigerdirect.com/applications/SearchTools/item-details.asp?EdpNo=4434989&CatId=493[/url]

The chip runs consistently from 40-44C. I have it overclocked at 160MHz x 21 = 3.36GHz and it's really running well.

I'd highly recommend a better cooler. The one I installed is large and required me to completely remove the motherboard for installation. Also, make sure your case is large enough to accommodate any cooler you choose.

-- Rich

[QUOTE=monst;202262]IThe chip runs consistently from 40-44C. I have it overclocked at 160MHz x 21 = 3.36GHz and it's really running well.[/QUOTE]

WOW...

I have the Noctua; OC'd to 3.2 just using EasyTune and it runs at 60C.

The cooler was too big for my case so I left the sidewall off.

[QUOTE=garo;202240]Absolutely no reason to go for one of those from a GIMPS perspective. An i5-750 is $199.99 so why would I spend the same money for a dual core?[/QUOTE]

Oops, sorry....missed the Dual Core part.

That is a very nice temperature. With the Noctua I got 44-45 at stock but at the current speed of 3.8GHz and 1.375V, I get about 62-64C with an ambient of 20C.

I'm very disappointed by the core i5 750 performance running 4 LL's. Overclocked to 3.0 GHz is only 15 % faster than my previous processor, a Q6600@2.9GHz. I though at this stage to have at least a gain of 30 %. Looks like I need to overclock even further.

[QUOTE=em99010pepe;203558]I'm very disappointed by the core i5 750 performance running 4 LL's. Overclocked to 3.0 GHz is only 15 % faster than my previous processor, a Q6600@2.9GHz. I though at this stage to have at least a gain of 30 %. Looks like I need to overclock even further.[/QUOTE]

My only point of comparison is to my Q9500 (stock 2.87) and my i5-750 (stock 2.66) which is impressive. The benchmarks for 1280FFT are 22 and 20 ms respectively. Running 1 core that is what I get. BUT running 4 cores the Q9550 drops to 28 ms while the i5 is virtually unchanged at 20-21 ms.

I usually say anything less than an order of magnitude performance improvement is negligible (that is to say I can hardly tell the difference). Makes my machines last longer that way at least. I don't have to start looking for replacements till they're over 3 years old, often much more.

[quote=petrw1;203569]My only point of comparison is to my Q9500 (stock 2.87) and my i5-750 (stock 2.66) which is impressive. The benchmarks for 1280FFT are 22 and 20 ms respectively. Running 1 core that is what I get. BUT running 4 cores the Q9550 drops to 28 ms while the i5 is virtually unchanged at 20-21 ms.[/quote]

Maybe for larger FFT the gap will open on performance. I am testing numbers of size n=1.9M, 1.7 ms. Now I overclocked even further and I am getting timings of 1.5 ms. I need a few more hours to have some results.

Carlos

Benches

[B]Q6600@2.9 GHz[/B] (Vista 64-bit, 6 GB DDR2 800 MHz)

15*2^1944026-1 is not prime. LLR Res64: DDBA8FB8DA55A41A Time : 3818.427 sec.

[B]Core i5 750@3.47 GHz[/B] (Windows 7 64-bit, 4 GB DDR3 1333 MHz)

15*2^1946425-1 is not prime. LLR Res64: 49B16A7783DC25F1 Time : 2930.602 sec.