I am building a PC, and am a bit overwhelmed at the cost. I can either get an i7 with a Geforce 660 or 750ti or I can get an i5 with a better GPU. Also, I bought a micro-itx case to save room on my desk, but perhaps this is foolish. I don’t know if the micro-itx motherboards are capable of competing with the normal ones. Also, does RAM speed matter, or should I just go for 1600? (I am totally clueless about the timing, and perhaps that matters as well).
So…when rendering in Cycles, does the CPU matter, or is it all offloaded to GPU these days? For final render, does the CPU matter much? Can I even get away with the i3, or should I just get the i7 and maybe get a bigger ATX case and spend more money on a video later… sigh.
About micro-ATX, that’s what I have and I a really happy with it. I think it totally can compete ATX motherboards in term of performances (which you will probably never feel, as most of us) EXCEPT not all microATX MB will allow you to get a multi-GPU system. This part will depend on your needs.
i5 CPUs are fine, except they do not have hyperthreading (meaning 4 core = 4 threads) contrary to i7 CPUs. This is actually the bigger difference between i5-4690 and i7-4790 for example. Hyper threading improves performances in multithreaded tasks, and it is true for cycles CPU rendering and probably for physics simulations and compositing too. I think i3 CPUs would be a bottleneck if you expect to perform a lot of computing.
RAM speed will probably not be a critical point, I’d say 1600 will be fine and save money.
GPU depends on what you want to do. If you get a smaller one you could add another for multiGPU IF YOU HAVE OTHERS PCIE SLOTS AVAILABLE. If not, you might want a better GPU.
If you just want to render some pictures and enjoy cycles a 750ti will be fine (and adding another could even bring you to really good performances), but if you want to be first in benchmarks you will probably go for 3x 780ti…
The more precise about what you want to do, the more precise the advises you’ll get.
I7 only, no doubt. 2x speedup ANY tread tasks of any thread aware program. GPU can be fast in some cases, but it is not ending minefield, onboard memory limit, changes in driver, etc.
That is simply not true. The speed increase in rendering is about 10-15% with hyperthreading. Tested overclocked i5 and i7 Sandies head to head @ 4,4 Ghz just recently in Cinebench and Blender. But yeah, if you can, get an i7.
When testing the spead increase of hyperthreading with my i7 2600k@4.5Ghz i got about 30% faster times with it turned on.
Just go with something like an Xeon E3-1231v3. It is cheaper then the i7(around 80EUR) and got Hyperthreading, the downside is that you can´t overclock it but it is as fast as an overclocked i5. As you can´t overclock the Xeon it will probably also save you some money on the mainboard.
Yes, i just checked in random scene, 8 bounces, 3770K, 8 threads 2.21, 4 threads 3.29. 65 % increase, not 100%. Maybe i tested on very HT friendly scene, it was year ago, but that was exactly 2x scale. Anyway, i vote for most powerful CPU you can afford, and rest on GPU.
My four year old 150€ GTX 460 is about 20% faster then my two year old i7 3770k (standard clock speed) which did cost 330€
My new 350€ GTX 970 is about 400% faster then my i7 3770k which did costs 330€
The i7 is (according to guy above and benchmarks) 50%, 60% faster. with an i7 costing around 300€ and an i5 200€.
If you want fast renders, a GPU will get the job done a heck of a lot quicker. however you have limited VRAM. So unless you do tons of compositing, and/or doing simulations (Cloth, Smoke, Water etc.) or enormously memory heavy scenes, Nvidia GPU oriented rendering does a sweet job.
You might even look into going with mid-core on both and rendering primarily on Renderfarms depending on what your prioritises are.
The recent NVIDIA GPUs like the 970 and 980 comes with 4G of RAM at least, if this enough for your scenes then you do not need a flagship CPU, you can use an i5 or even an AMD. I’m using an AMD FX 6300 (~100Euro) and it’s scoring almost as good as the i5 and i7 machines using the same GPU (BMW benchmark).
I would recommend you to save money on the CPU and invest in a good GPU and also SSD.
Another warning about the MicoATX case is physical size. Some GPU cards just won’t fit in those tiny spaces. Or if you get them to fit there is not enough room for adequate cooling. Buy a real full-size case and motherboard if you can. Later on you may want to add something to this machine and with the MicroATX you may not have any room left.
Choose the i7 and the 750ti over the 660GTX. More GPU ram is better, at this point 2GB is really just not enough.
@John5200 We are just arguing about how useful Hyperthreading is on a current CPU(can´t believe that it is above 50% from my experience). Maybe the i7 is 50% faster if you compare an i5 with an i7 with standard clock speed but with equal clock speeds the difference shouldn´t be that high(still high enough to matter).
I don´t say that he shouldn´t get a fast gpu - The Xeon i mentioned above is around 50EUR more expensive then the i5 but around 80EUR cheaper then an i7. An GTX660 + i7 costs around 450EUR, an GTX970 + i5 costs around 450EUR and the GTX970 + Xeon which would give him the best of both worlds is only 50EUR more expensive.
I can´t recommend getting an AMD CPU for your workstation as there are several tasks where you will need the single-thread performance of the Intel-CPUs.