i7 870 vs i3 2120

[Team kizb]

I'm looking at picking up a new S@H cruncher that has an i7 870 2.93GHz installed. Since 1156 is a dead end my thinking was to pull it and go with a new 1155 MB with my current i3 2120 3.3GHz

What should do better? An older i7 Quad core w/ HT, or a newer i3 Dual core w/ HT?

This rig will also be running duel video cards and be ran 24/7.

[Rickdstik]

Go with the i7 Quad. Even though you're running GPU, there is some CPU overhead that's needed to feed the GPU. Plus the i3 being a Sandy Bridge is not overclockable much where the i7 will overclock to 3.6+ Ghz easily.

[EarthDog]

You can permanetly select the turbo multi on those i3 non overclocking chips and get VERY little bclk. I would imagine with turbo and the platforms better efficiency (clock for clock performance) it should be the same as the overclocked 870 (with its turbo multi locked and bclk adjust of course).

I dont know how Seti crunches though so excuse me if I am missing something. :)

[Rickdstik]

Stock for Stock, passmark shows about 2/3 performance on the i3 vs the i7. Drops down to about 55% when an average overclock is applied. Granted, this is a general benchmark, and can't be completely applied to all processes, but that should give you a general idea. If you're concerned about your power bill, the i3 is by far the better option, despite the lack of overclock. If raw performance is your goal, the i7 is going to end up being better.

[EarthDog]

What is passmark? And what in its testing does Seti use?

[Rickdstik]

PAssmark is a general CPU benchmark. SETI uses its own internal benchmark to test cpu performance ... I need to go see if i can find a stock i3 and stock 870 to compare.

[Rickdstik]

Credit per second (by CPU)
i7-870: 0.001713
i3-2100: 0.000145

Source: http://boincstats.com/stats/host_cpu_stats.php?pr=sah&teamid=&st=200&or=

[EarthDog]

Im shocked at the difference...its almost 10 fold...! Thanks for the info. :)

[4GHZ_or_bust]

If you already have mobo, an i7 would do better. If you don't have a mobo, a socket 1155 and i7 2600 or 2700 would probably be your best bet. I have 2700k and it overclocked all the way to 5.3GHz and still boots. Not stable above 5GHz tho but 5GHz is much better than any of the older socket 1156 can do on *air* cooling.

[Rickdstik]

Of course, there's no telling how many of those CPUs are/arent running optimized either. I suspect more of the 2100s arent since that's a Dellbox type CPU where the 870 is more something a power user would use. I suspect the real differnce on optimized clients is significantly less than 10 fold.

[Team kizb]

If you already have mobo, an i7 would do better. If you don't have a mobo, a socket 1155 and i7 2600 or 2700 would probably be your best bet. I have 2700k and it overclocked all the way to 5.3GHz and still boots. Not stable above 5GHz tho but 5GHz is much better than any of the older socket 1156 can do on *air* cooling.

Yes, I would already have a 1156 MB, an ASUS Maximus III GENE. Looks like just using it as is for now is going be the way to go. Thanks all for the great information and numbers.

[Team kizb]

For SETI crunching, would to be worth it to upgrade from an i7 870 to a i7 2600K?

I already have an 870 and MB, but have been considering picking up a 2600K and new MB and selling the 870 setup. This rig will also be running 2x 560 ti 448 cards.

[Rickdstik]

BoincStats has the 2600K @ 0.008260 credit per second and the 870 @ 0.001713. Again, this is not taking into any kind of consideration of optimized clients. Given that, the 2600k will be faster. Worth the upgrade, not sure about. Ivy Bridge is just around the corner, and I think we'll see big things from it.

[4GHZ_or_bust]

Overall there's probably no difference between i7 unless you go into overclocking as 2600k can overclock much higher.

Personally I'd wait for the next gen CPU to see if you can get better bang for the buck.