pci express version

Hello.
can some one explain me how to calculate Maximum supported card befor bottleneck?

for example i have Pci express v2.x: 500 MB/s (5 GT/s)
and geforce 880m

GeForce GTX 880M | Specifications | GeForce

what is geforce 880m "buss speed"
will Pci express v 2 be a bottleneck?

 

With PCIExpress 2.0, bus throughput is indeed ~500MB/s, but that's for PCIE x1 link. Your GPU works on a PCIE x16 link, so it has 16x500MB/s = 8GB/s link to the CPU (bi-directional).
For PCIExpress 3.0, bus throughput is effectively doubled (1GB for x1 link, 16GB/s for x16 link). For upcoming PCIExpress 4.0, bus throughput will be doubled again (2GB/s for x1 link, 32GB/s for x16 link).
Even with PCIExpress 2.0, bus speed will never be a bottleneck for your GPU. Many IT portals performed comparisons when PCIExpress 3.0 was introduced, the same GPUs running on PCIE 2.0 and PCIE 3.0 were compared, there was no difference in their performance.

How come you have GTX880M on a system with PCIE 2.0? All laptops with this GPU were released with Haswell CPUs, therefore PCIE 3.0. Just curious...

 

i am on 680m with pci-e 2.0

thinking about trying 980m in my config, but i need more info=)

but is thera an option to calculate GPU "required" GB/s ?

 

Sorry, I've never heard of anything like it.

 

PCI/e 2.0 x8 will not bottleneck any single GPU on this planet that is currently in a released format. You need not worry.

 

Pci 2.0 4x/3.0 2x would impact performance to a noticeable %. That's the point you want to avoid. Higher lane counts matter for multi gpu setups.