Bugger 
I'm afraid the only solution left then might just boil down to getting a new videocard.
Don't be daft !
Freespace itself runs absolutely perfectly
Wing Commander DD mod runs absolutely perfectly
Derelict mod runs perfectly
Blue Planet mod runs perfectly
Destiny Of Peace (Silent Threat etc) mod runs perfectly
Halls of Valhalla runs perfectly
Storm Front runs perfectly
Sync runs perfectly
Transcend runs perfectly
etc etc etc
Between The Ashes is however Daffy Ducked
As is Wings of Dawn
This clearly suggests that the developers of those mods have messed with something that they shouldn't have
That they have tweaked settings that are specific to certain hardware or software rather than leave things more generic
I'd like to play those mods, but FFS I'm not going to buy specific hardware to be able to, that's crazy.
Even if I did, do they even know themselves what hardware is specifically needed? There's no recommended hardware that I know of.
If ALL mods were affected by this text garbage crap then yes, different hardware would be a reasonable suggestion.
Since most mods work perfectly then the problem lies very obviously with those 2 mods. It's really up to the developers to fix it.