Crossfire compatability

[Donny John]

I have the X-Edition VTX 7770 (1100 Mhz GPU/5000 Mhz memory) and am wondering if that card will be compatible with a regular/vanilla 7770 (1000 Mhz GPU/4500 Mhz Memory) in Crossfire.

If it matters, the motherboard is a Gigabyte GA-970A-DS3.

The X-Edition is not available any more and I have been offered a cheap MSI 7770 card.

The VTX HD 7770 doesn't appear to have a Crossfire Bridge Port/connector.... I don't need a bridge? Some people are suggesting I do, but there's no connector port for a bridge and a quick check on Wiki says that later models do not require it!

Also.... R7-250X... will that work in Crossfire with the 7770? (same core but way different speeds).

[Shivy011]

The two 7770s should crossfire, not sure about the R7 250X though

[Donny John]

The VTX HD 7770 doesn't appear to have a Crossfire Bridge Port/connector.... I don't need a bridge? Some people are suggesting I do, but there's no connector port for a bridge and a quick check on Wiki says that later models do not require it!

[scaryjim]

All 7770s should have a cross-fire bridge connector - the gold "finger" just near the backplate? Although I guess it could've been left off for cost saving purposes, but it seems a bit odd.

Crossfire might well work without a bridge - a lot of low end AMD cards in the last few gens could do crossfire across the PCIe bus, and all the genuinely new cards do (but they've got special features baked in to the silicon to allow that). I suspect performance would suffer a bit for a card like the 7770 that's *meant* to use a bridge.

Also, have you considered the fact that the second PCIe slot on your motherboard is only an X4? That wouldn't normally make a *huge* difference, but if you're having to push all the crossfire overhead through the PCIe bus too it could have a noticable impact.

Check whether your card has the crossfire finger - if it has you should see a decent uptick in performance from going crossfire. If it doesn't, I think I'd personally just look out for a 260X or 265 on special offer, which would be a more reliable, less title-variation-prone upgrade...

[Bonebreaker777]

Donny is right, the VTX HD 7770 doesn't seems to be having a Cross-fire bridge connector. On the other hand, the features does mention Cross-fire support what is that all about???

http://www.vtx3d.com/products_features.asp?id=165

Rather odd. But taking into account the low cost of VTX cards in general, the lack of the connector maybe be indeed a cost saving solution. Most unusual. Worst case, could you borrow a HD 7770 from somewhere or even better, buy one from a retailer who offers 7day no-questions-asked return and if doesn't works out, send it back for some other card.

[scaryjim]

I thought Donny had the "X-Edition" version? Looking at the fourth picture here http://www.vtx3d.com/products_features.asp?id=162 it appears to have a crossfire finger!
apologies, that's the 7790 X edition - the VTX page doesn't seem to list the 7770 X-Edition!
OK, so there are 2 VTX 7770 X-Editions: this one: http://www.vtx3d.com/products_features.asp?id=133 definitely has a crossfire finger, this one: http://www.vtx3d.com/products_features.asp?id=118 may or may not, I can't tell from the picture (or find a picture on Google to confirm)!

AMD cards have been able to do crossfire through the PCIe bus only for a fair while - the reference 7750 was specified without finger/bridge, for instance. I'd always assume it was a performance-based decision from AMD - presumably the more powerful the card the closer the PCIe bus gets to saturation, so the greater the benefit of a crossfire bridge.

I think the bottom line, OP, is that whether your card has a crossfire finger or not, crossfire should still work

Although as I said previously, I'd be concerned about running bus-only crossfire through an x4 connector....

[Donny John]

The card DOES have a Crossfire connector... I am blind it seems.

The chap who was letting me have the MSi 7770 cheap, has admitted that it doesn't seem to work properly. I'm putting this on the backburner, I'll wait and see what happens with prices over the next few months.... summer (dead season) bargains will be heading our way soon.

Thank you for the advice everyone. I will probably go the direct card replacement route if there's a worthy upgrade that's priced right.

[Bonebreaker777]

I thought Donny had the "X-Edition" version? Looking at the fourth picture here http://www.vtx3d.com/products_features.asp?id=162 it appears to have a crossfire finger!
apologies, that's the 7790 X edition - the VTX page doesn't seem to list the 7770 X-Edition!
OK, so there are 2 VTX 7770 X-Editions: this one: http://www.vtx3d.com/products_features.asp?id=133 definitely has a crossfire finger, this one: http://www.vtx3d.com/products_features.asp?id=118 may or may not, I can't tell from the picture (or find a picture on Google to confirm)!

AMD cards have been able to do crossfire through the PCIe bus only for a fair while - the reference 7750 was specified without finger/bridge, for instance. I'd always assume it was a performance-based decision from AMD - presumably the more powerful the card the closer the PCIe bus gets to saturation, so the greater the benefit of a crossfire bridge.

I think the bottom line, OP, is that whether your card has a crossfire finger or not, crossfire should still work

Although as I said previously, I'd be concerned about running bus-only crossfire through an x4 connector....

Missed the "X" at the beginning of the thread. Pffff. Justification to keep wearing glasses I guess :-D

[polosistealth]

no way will it work it 250x in crossfire....