Originally Posted by Retrorockit
I have some specific needs in a video card for an older computer. I purchased a couple of cards that were too new and didn't support support the BIOS in my older computers. I'm building another old computer that has Crossfire support. For now Ill be using a pair of HD6970s I already have. I'm looking for the most powerful video cards that are compatible with my old architecture. The HD7970, and related R9-280X look like they might be what I need.
I've made a hobby of overclocking old Dell BTX computers. Specifically LGA775 stuff.
This means locked BIOS, no aftermarket cooling parts available, Legacy BIOS usually. PCIE 16x 2.x ,and SATA 3GB speed.
The problem I've had in the past is with R9-285 ITX cards.
First problem is they don't support VESA video mode 103. So can't open my BIOS Setup screen.
The second problem is I can't Crossfire them because the ITX cards are a little thicker than normal 2 slot cards and there's no room for airflow into the second card.
The Sapphire cards I used have a dual BIOS switch, so they're not only compatible but future proof also. (Except for VESA 103 issue.)
The VESA mode 103 issue seems to have started with the R series cards. I know of 1 person who Crossfired a pair of HD7850s in the same computer I'm working on. So I think HD7970 should work. I've seem reports that HD7970 can Crossfire with R9-280X also.
Here's what I think I need.
1- Legacy BIOS support, preferably Dual BIOS.
2- Vesa mode 103 to display Dell BIOS screen. (AMD says GCN cards don't support this.) HD7xxx seems good for this.
3- Crossfire bridge connection due to PCIe v.2.0 speed.
4- More than 2 GB memory would be nice
I've tried AMD, Sapphire, and the usual BIOS mod suspects ( MB, and GPU ) and haven't found a solution.
My last project was a Dell Dimension E520. This Pentium 4 era beast ran a QX6800 at speeds up to 4 GHZ (validation only) and at 3.72GHz, and with an R9-285 scored 7000 in Firestrike (58% rating). See link in my sig.
My current project is a 1 year newer Dell Precision T3400 workstation. It supports QX9650, and 2- PCIe 16x full speed slots. VESA mode 103 still applies. I will probably start out with a QX6800, and HD6970s. this will tell me a lot about the MB VRM and cooling system mods.
Any advice on which video cards would be suitable for this would be appreciated. Especially any Brands that don't support my requirements.