Hi There !

I want to build a new computer for seti home. What worth to buy for. Corei7 series are very expensive, but the 2.67 ghz one is very cheap and maybe have much power when its overclocked. Whats your experience about the core i7 processors, and is there a high difference between a 2.6 ghz procesor and a 3.0ghz processor in this brand ?

If I were going to build a system right now, I'd probably build it around a core i7 860 and put in a couple of GTX 260 cards. But for me, that would only mean getting a motherboard, processor, adapter for the processor heatsink, a couple sticks of DDR3 memory and the GTX 260 cards - I'd recycle other components for the rest. But if you're going to just do CPU processing, go for the i7 920, it can be purchased pretty cheaply. Generally speaking, it depends on how much you want to spend and how much power you want to use.

-Dave

---

yes I was thinking about only with CPU processing, but I dont know the actual seti status on gpu processing because I've read that you cannot use your gpu and cpu at the same time, but maybe this information is outdated.

So i7 920 is good priced the i7950 have almost double price and maybe I can reach the same result when if I overclock the i7920 one.

with the i7 series, the l2 cache is low compared to q series. i7 has 256 KB per physical core and 128 KB l2 if it's hyper-threaded. that the only draw backi see in an i7 cruncher. info per newegg.

The i7 processors have 8M L3 cache, plenty for Seti and they've proven to process quite well. If you're into OC-ing, you can do pretty well with a 920, and definitely exceed the stock speed of the 950, just make sure you have good cooling.
As for using the processor and GPU at the same time, you certainly can do that, you just need to remember that the GPU has to be "fed" by the cpu, so you would want to leave a core or 2 (depending on the number of GPUs) free for maximum processing on the GPU, otherwise there is some contention for resources.

-Dave

[edit - spelling]

---

If you happen to live near a Micro Center store, they have i7 920 @ $199.99.
As I see it, the only issues with this CPU are:
- upgrades (since use different socket than i7 860)
- system power consumption/mobo heat generation (this has mostly to with the x58 chipset than the CPU)
- you have to use 3 sticks of memory
Advantages:
- triple channel memory
- proven overclock numbers
- multiple 16x PCIe sockets (new P55 goes to 2 x 8 channel when 2 x videocard used (NOTE: this is unimportant for SET use)

Overclocking X58 and P55 motherboards can be pretty expensive.

For high SETI RAC, use multiple nVidia cards - and use a power supply to match!

I might also note that ATI is introducing new videocards that very possibly will result in lower prices for some (all?) of the faster current nVidia based cards. Rumor has it actual ATI availability date = Sept 23.

Put your $$ into a GPU or 2, the CPU is almost irrelevant . You really only need one run Boinc to feed GPUs.

Looking at the top hosts list, you are down to #60 before you find the first CPU only machine, and thats got 4x quad cores.

Plenty of normal quad cores above that on the list, but with multiple CUDA cards.

I7s are a good CPU and crunch well, but a much cheaper quad, in a cheaper board and ram etc will beat it hands down with a better GPU.

So if money is no object , get an I7 AND a couple of GPUs. But if you have some sort of $$ limit like the rest of us mortals, spend the $$ on a GPU.

It also depends what else you are using the machine for.

Ian

If you happen to live near a Micro Center store, they have i7 920 @ $199.99.
As I see it, the only issues with this CPU are:
- upgrades (since use different socket than i7 860)
- system power consumption/mobo heat generation (this has mostly to with the x58 chipset than the CPU)
- you have to use 3 sticks of memory
Advantages:
- triple channel memory
- proven overclock numbers
- multiple 16x PCIe sockets (new P55 goes to 2 x 8 channel when 2 x videocard used (NOTE: this is unimportant for SET use)

Overclocking X58 and P55 motherboards can be pretty expensive.

For high SETI RAC, use multiple nVidia cards - and use a power supply to match!

I might also note that ATI is introducing new videocards that very possibly will result in lower prices for some (all?) of the faster current nVidia based cards. Rumor has it actual ATI availability date = Sept 23.

You dont have to use 3 sticks of ram... you only have to do that if u want to use triple channel... x58 will do single, dual or triple channel. If you go for the 920 try and get the SLBEJ version which is the D0 stepping... Apparently this stepping is more overclockable than the original stepping. An i7 920 with dual/triple channel and multiple (NVIDIA if youre doing this for seti) graphics cards is a good way to get a massive rac on one machine. DDR3 triple channel sets are pretty cheap these days and you can get an x58 motherboard pretty cheap these days

---

yes I was thinking about only with CPU processing, but I dont know the actual seti status on gpu processing because I've read that you cannot use your gpu and cpu at the same time, but maybe this information is outdated.

You can. But best config depends from how many and how fast GPU used and how many and how fast CPU cores are.
For some cases better to leave CPU for feeding GPU only.
But you need very fast and not just one GPU for this condition.
Midrange GPUs just very nice addition to quad core CPU fo relative small price.
For example, 9600GSO can work as ~2 cores of Q9450 giving 6 "cores" total.

FYI: I have a dual AMD Barcelona 2.1GHz setup (8 cores) with 2 x GTS 250, and each GTS 250 puts out more WUs than the 8 cores; it's the equivalent of about 32 - 40 cores all together. So yes indeed, GPUs MUCH more important than CPUs, and use less power, too.

---

>> You dont have to use 3 sticks of ram... <<

I "misspoke" - thanks for the clarification.
...although I can't really see anyone setting up a new machine without 3 sticks...

>> You dont have to use 3 sticks of ram... <<

I "misspoke" - thanks for the clarification.
...although I can't really see anyone setting up a new machine without 3 sticks...

For the price difference, I'd use three if the board supports tri-channel...

-Dave

---

indeed... i would always use 3 aswell, but if someone is in the middle of building and has some spare ddr3 lying around in single or dual channel and wants to spread the cost over a little while then they dont need triple channel straight away! :)

---