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PCI Express Bandwidth query

CurlyWhirly

CurlyWhirly

CurlyWhirly

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According to GPU-Z (below) my graphics card has 72 GB of bandwidth but I think this related to the video RAM and am not sure whether it is limited by the PCI Express interface or not :confused:

28a7z40.jpg



How do I know whether my PCI Express interface is bottlenecking my graphics card when I upgrade in the future?

GPU-Z says that I'm using a 16 bus interface and on wikipedia it states:

Capacity per lane:

* v1.x: 250 MB/s
* v2.0: 500 MB/s
* v3.0: 1 GB/s
Click to expand...
How do I know which version I'm running?

All I would like to know is the maximum bandwidth that I can put in my PCI Express interface (via the graphics card) before technical limitations 'kick in' ?


I've heard about PCI Express 2.0 that doubles the bandwidth per channel but am not sure if it is the same as the 500 MB/s reference in my above quote?


I don't think that my motherboard supports this new feature as it's a budget mobo not an overclocking mobo - is there any way to find out?

My mobo is a Foxconn G31MX Series motherboard.

Thanks.
 
I don't get you. It tells you that its PCI-E x16 @ x16 which means it's running at full speed on a PCI-E v1 slot (your motherboard doesnt support PCI-E 2), and if my mathematics is right that means you have up to 4000mb/s (Bandwidth) to use on that slot and a 2500Mhz bus speed.
 
9800GTX generation card won't be bottlenecked by a PCI-e x16 gen 1 slot at all, infact even a x8 PCI-e gen 1 slot would be sufficent in 99% of cases.

You'd have to go for a 4870 or 200 series card to really be bottlenecked by a x8 PCI-e gen 1 slot at all.
 
That 72.0GB refers to Memory Bandwidth, that's the internal bandwidth of the memory on the card. It does not directly interface with the PCI-E slot.
 
Once the textures and assets have been loaded into the graphics cards ram, the actual amount of data transfered drops considerably. Worse case you may find loading times higher on a slower PCI-E slot.

As long as the slots are electrically compatible, you should be able to take future upgrades without worrying about the slot's bandwidth bottlenecking.

To be honest, when it comes to "future", CPU's and Ram are more likely to be performance bottlenecks, and an upgrade to i7/i5/ifuture will entail a new motherboard anyway.

If the card plugs in and works, then slot bandwidth is pretty much last place for things to worry about.
 
racerboy59 said:
I don't get you.
Click to expand...
I'm new to PCI-Express as I've only recently upgraded from AGP so my knowledge of it is limited :o



racerboy59 said:
It tells you that its PCI-E x16 @ x16 which means it's running at full speed on a PCI-E v1 slot (your motherboard doesnt support PCI-E 2)
Click to expand...
Not a very future proof motherboard then :(



racerboy59 said:
and if my mathematics is right that means you have up to 4000mb/s (Bandwidth) to use on that slot and a 2500Mhz bus speed.
Click to expand...
Thanks for that but I can't see how this 4 GB bandwidth fits in with the 72 GB bandwidth (which is memory based) and the Pixel Fillrate and the Texture Fillrate which are measured in GPixel/s and GTexel/s respectively :confused:
 
Rroff said:
9800GTX generation card won't be bottlenecked by a PCI-e x16 gen 1 slot at all, infact even a x8 PCI-e gen 1 slot would be sufficent in 99% of cases.

You'd have to go for a 4870 or 200 series card to really be bottlenecked by a x8 PCI-e gen 1 slot at all.
Click to expand...
That's good news :)
 
Corasik said:
As long as the slots are electrically compatible, you should be able to take future upgrades without worrying about the slot's bandwidth bottlenecking.

To be honest, when it comes to "future", CPU's and Ram are more likely to be performance bottlenecks, and an upgrade to i7/i5/ifuture will entail a new motherboard anyway.

If the card plugs in and works, then slot bandwidth is pretty much last place for things to worry about.
Click to expand...
It seems that I'm worrying over nothing then.

I'm only curious as to whether it would be worthwhile upgrading to the next generation of graphics cards when they are released at the end of the year.

I wasn't sure if the graphics card would be bottlenecked severely or not (as my mobo doesn't support the PCI-E 2 standard)

Thanks to everyone for their feedback :)
 
In all honesty it will still be a while before PCI-E v1 is the bottleneck on single card setups. Unless you are on SLI or crossfire you'll be fine with what you have. Just as it was the case with SATA 150 and SATA II (300).
 
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