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Grizzly
15-06-2012, 08:01 PM
Right. I have recently aquired a motherboard Asus P5Q-EM; with a Q6600 Core 2 Quad, 4 gigs of so called "Hyper X" ram, and a power supply of 480 watt - and I have to pay 120 euros for it - then it is all mine.

I am looking to build a rig out of this (screw the Arma 3 requirement!) and was looking for a suitable graphics card to fit with it. I was looking at the ATI 7750. However, there is a small problem

The motherboard supports PCI express 1.1
The card is a PCI express 3.0
They are compatible in theory - I am afraid that they will not be in practice. Recommendations?

djbriandamage
15-06-2012, 08:23 PM
I'll help you out tremendously by giving you a nebulous answer full of doubt.

I know for a fact that many, if not all, PCI-E 2.0 devices are compatible with PCI-E 1.0 and 1.1 slots. Furthermore, many, if not all, PCI-E 2.0 slots are compatible with PCI-E 1.0 and 1.1 devices.

I've read that a PCI-E 3.0 slot is compatible with PCI-E 2.0 devices, and PCI-E 3.0 devices are compatible with PCI-E 2.0 slots.

No idea if compatibility spans 2 generations, though, as there are some fundamental design differences between each PCI-E generation which I totally don't understand.

TL;DR, iono!

You're welcome.

kalniel
15-06-2012, 09:34 PM
The motherboard supports PCI express 1.1 The card is a PCI express 3.0 They are compatible in theory - I am afraid that they will not be in practice. Recommendations? Well you've diagnosed it correctly. They should work, but unless someone has tested it, you can't know for sure. Pop an email to Asus and they might be able to help - last time I had the same query from an Asrock board they found one in the warehouse (it was an old motherboard by that point) and actually tested it for me before answering.

kalelovil
16-06-2012, 05:12 AM
All PCI-e versions should be fully forwards and back compatible.
The only exception I am aware of are some early PCI-e 1.0 Via chipsets which had problems with PCI-e 2.0 graphics cards.

Kamikaze-X
17-06-2012, 02:36 PM
All PCI-e versions should be fully forwards and back compatible.
The only exception I am aware of are some early PCI-e 1.0 Via chipsets which had problems with PCI-e 2.0 graphics cards.

this.

/10char

Proctor Eldritch
20-07-2012, 08:38 PM
All PCI-e versions should be fully forwards and back compatible.
The only exception I am aware of are some early PCI-e 1.0 Via chipsets which had problems with PCI-e 2.0 graphics cards.

So it would be safe to purchase a PCI-e 2.0 gpu for a mobo with PCI-e x16 (Gen 2.0) ?

byteCrunch
20-07-2012, 11:03 PM
Right. I have recently aquired a motherboard Asus P5Q-EM; with a Q6600 Core 2 Quad, 4 gigs of so called "Hyper X" ram, and a power supply of 480 watt - and I have to pay 120 euros for it - then it is all mine.

I am looking to build a rig out of this (screw the Arma 3 requirement!) and was looking for a suitable graphics card to fit with it. I was looking at the ATI 7750. However, there is a small problem

The motherboard supports PCI express 1.1
The card is a PCI express 3.0
They are compatible in theory - I am afraid that they will not be in practice. Recommendations?

You will probably need to update your BIOS to support a PCI-E 2.0 or above card, on a PCI-E 1.1 slot. Your motherboard manufacturer should have released an update to support later GPUs.


So it would be safe to purchase a PCI-e 2.0 gpu for a mobo with PCI-e x16 (Gen 2.0) ?

The only thing that really changes between PCI-E versions is the bandwidth, even though you'll be hard pushed to even fully saturate PCI-E 1.0. The only thing you need to watch out for is if you are trying to put a PCI-E 2.0 GPU in anything less than PCI-E 1.1 (though this can vary by motherboard), 1.0 doesn't have the power throughput.

Eric
20-07-2012, 11:22 PM
It should work, no bios updates necessary.

As for the bottlenecks from using a PCIe 3.0 card in a PCI 1.1 slot, I'm not sure, the the difference between a 2.0 card in a 1.0 slot, is almost negligible (http://www.techpowerup.com/reviews/NVIDIA/GTX_480_PCI-Express_Scaling/24.html), so perhaps it'll be noticeable with your setup. Then again your CPU will probably be a bottleneck before you need to worry about saturating the bandwidth of the PCIe slot.


Also, just to say if you're worried about your CPU and the Arma 3 requirements, the Q6600 overclocks very nicely, you should be able to see gains of at least 1 GHz, without much tinkering.