If I'm rending with the GPU, do I need an i7 processor for Blender?

If you can afford an i7 then you should go with it.

Apart from rendering the processor is used for physics simulations too.

Cycles is a very good renderer but still in development and many features in cycles are enabled only when you use CPU for rendering plus if you decide to use any other external renderer like yafaray or luxrender i7 will always be an advantage.

But if you have decided you will only use GPU for rendering and you will not have lot of Dynamics/Physics simulations in your scenes then you can stick with i5.

Hope this helps..

Blenjoy...

http://animonkz.blogspot.com/

you will see an important volume of deference with the 3770k over the 3570k whilst video modifying. in case you have been in basic terms gaming i could defiantly say you're able to pick the 3570k as hyper-threading provides 0 overall performance strengthen in 98percentof all video games as much as now and could additionally drop your FPS a touch over the 3570k. I actual have the two the 3570k and the 3770k, i can tell a particularly good overall performance strengthen whilst video modifying with the 3770k. the final suggestion i'm going to provide you is that in case you artwork greater then you definately play then get the i7 3770k yet once you interest greater then you definately do artwork i could pick the 3570k and the 650ti strengthen, because of the fact the HD4000 I-GPU isn't even nicely worth attempting to play AAA a tittle video games with. in case you probably did farmville and little video games like that the HD400 I-GPU could be great and could do basically high quality, yet extreme video games desire detected GPU's in case you desire to play them like they have been meant to be performed. wish this helped you, ericlee30 ~Member Of The Intel reaction Squad~

No

Blender is not heavy on the CPU only the GPU

There is NO point upgrading it's a waste of money if your rendering with the GPU

i5 will work just fine for that. No need to spend the extra money for an i7.

i7 is a heck a lot better, but i5 will do