Hello, I'm doing a build for my friend who will be doing some light gaming. Although I have built numerous PC's before, I must say, I am an absolute noob when it comes to APU's. I understand that he may opt to get a Radeon HD 6670 in the future to basically crossfire with the APU to increase the graphics performance, but I have a couple of questions regarding the compatibility and effect on performance:
1. He is using 2133mhz DDR3 ram, does that restrict him to 6670 graphics cards using DDR3 memory?
2. Will there be that much of a performance difference based on whether or not he buys the DDR3, GDDR3 or GDDR5 versions of the card. (I understand that in a regular build, it might differ slightly with GDDR5 being a tad bit faster, but perhaps when combined with an APU, there might be different constraints?).
1. RAM memory has nothing to do with GPU's own memory. Thus the memory that's on-board won't affect GPU in any way at all (unless available memory runs out, in that case "memory feeding" is allocated to GPU's memory and it will most likely to all go into drain very fast, if it's not 4+GB card, that is). In other words - you'll be fine as long as you have at least 8GB.
2. A10-5800K has entire HD 7660 on-board. That is quite powerful for an Integrated GPU. The performance boost will be quite significant if you add discrete GPU in the CFX with it.
No matter if it's of "GDDR 3" or "GDDR 5" levels, the boost will be significant nonetheless.
Of course, "GDDR 5"-level card will be quite better than older "GDDR 3"-standard card, but they'll both give big increase in overall video performance nonetheless.
1. Using the fastest system memory helps the apu because the cpu and apu share the system memory. 2. In duo graphics mode the speed of the gpu matters very little because the apu and gpu must work together they'll function at the speed of the apu, the apu can't run at the speed of the cpu.
1. Using the fastest system memory helps the APU, because the CPU and APU share the system memory.
He didn't say anything about APU. Read his post thoroughly and more carefully. He asked if RAM would affect discrete GPU.
2. In CFX mode the speed of the GPU matters very little.
That's exactly what I said. Difference between "GDDR 3" and "GDDR 5" video cards would be insignificant if CFXed with Trinity, but it will give boost nonetheless.
Everything else: well duh.
P.S. Also, about memory: the fastest memory should help more, but the problem is in that, the faster the memory is, the more unstable it is.
Thus getting ultra-fast memory if it's not supported by OS, is not a very good thing to do. Shenanigans may happen (and actually do happen quite in many cases).