DDR3 vs GDDR3 vs GDDR5

The ram on the graphics card has an effect on graphics performance.

It is totally separate from whatever type of ram you may have on the motherboard.

The higher the number at the end, the faster the memory. So GDDR5 is the fastest of those three (and it's usually a multiplier - so GDDR5 is 5x data rate whereas DDR3 is only 3x). The G is supposed to signify designed for GPUs, but often just is added for graphics cards with no real change in design. So DDR3 roughly equals GDDR3, and GDDR5 is faster. Thas said, you won't find main RAM labeled with the "G"

No motherboards support DDR5 as primary RAM - DDR3 is as high as it goes. And you can use a video card with any sort of vRAM as long as your motherboard supports the connector (PCI Express 2.0, AGP, etc), vRAM speed doesn't impact compatibility.

No offense but a lot of this is wrong, please don't explain stuff you don't know. The number is the version not the multiplier. Ddr3 (not gddr3), gddr4 and 5 all have a multiplier of 4 because gddr4 and 5 is based off of ddr3. Gddr3 is based off of ddr2 with multi of 2. And there is a real change in design in each. But these details really don't matter, the higher the number, the faster it is. And it doesn't matter what ram version your mobo has as vram is separate and unrelated.

Why going into deep details ?
@OP, the GDDR5 is has faster transfer rates than GDDR3/4.
As the RAM is used by the system to store data for processing by a computer's central processing unit (CPU) the VRAM is used to do the same for the GPU (Graphics Processing Unit) so DDR belongs to the CPU and GDDR belongs to the GPU.

Lets make it simple. Ddr 3 are ram they use on the pc. The Ddr 3 they used on the Gpus are the slower ram that was used before Gddr5.
Forget about the speed that it run posted with Gpus or the bus. All you need to know is that they use Samsung Gddr5 ram which has a effective clock of 1GHZ which equals 4GHZ. All the gpu manufacturers does they down clock the ram where the Brands like Msi, gigabytes ,sapphire etc etc will then just OC it higher making you think the card is overclocked a great deal. But in reality its still running under its stock of 1GHZ.
That's it