What I'm asking is how to calculate the GB/s of the GPU, not the video RAM.
Since the GFLOPS could vary depending on the various types of operation made, a throughput in GB/s would be more general and equal for all situations.
So, HOW DO I CALCULATE THE MAX THROUGHPUT IN GB/S OF THE GPU?
You simply can't do that , because the GPU usually have multiple different units that operate on different frequencies , and have different parameters too !
For instance , the GPU contains :
1-A hardware Rasterizer , it outputs one triangle every clock cycle , so the unit here is (Mtri/s) Millions of Triangle/S .
2-Texture Units , which outputs one texel every clock cycle , so the unit here is G Texel , or Giga Texel .
3-ROPS , which output one pixel every clock cycle , so the unit here is G Pixel , or Giga Pixel .
4-Shader Cores : already explained .
And for each type , you calcualte it's throughput , by knowing how many units are there , and there frequnecies , for example in GTS 250 :
There is
one Rasterizer , operating at 738MHZ so :
1 X 738 = 738
MTri
There are
64 Texture Units , operating at 738MHZ , so :
64 X 738 = 47.4
GTexel
There are
16 ROPS , operating at 738MHZ , so :
16 X 738 = 11.8
GPixel
There are
128 Shader Core , operaing at 1836MHZ so : 2 X 128 X 1836 = 470
GFLOPS
