Thanks for all your replies guys!
I'll try and clarify some of the points you'd queried about!
1) My computer is a six year old one - but even though that is a bit rickety in PC terms, it's a 2.8GHz quad core, it still handles Skyrim and Dead Island (though the old GPU starts smoking!). The OS is the old XP SP3 though. I have got a three month old machine I can try it on luckily!
2) I'm not really complaining about the tens of thousand of ships, I can always disable my own unit caps with the old cheats and have hundreds of thousands myself..... I'd love it! Quarter of a million ship battles! Woohoo! It's the PC not sharing the love thats the problem!
3) 460 doesnt seem that high an AIP..... I've had it up 1500! (and was only getting 10k reprisal waves at the time) >D
4) Someone asked what ships the 50k wave I had was, it was Mark IV Parasite ships if I remember right, but the nastiest one has been the 5k wave of Mark IV Raider Starships! I mean, I can only have 12 Raiders - and only 3 of them Mk IV's!
5) My HAP was nowhere near overspent, in fact the hacking that spawned the 5k Raider IVs was only the second "research redirection" hacking attempt in the whole game. However I was also keeping up a "sensor hack" in the same system at the same time!
6) About the point someone made about only capturing a few high reward systems - how do you get a decent number of research points built up from just a small number of systems? I've been needing them all! Every damn planet in the galaxy! >D
7) Someone mentioned hi-cap ships, like "Laser Gatlings"..... hehe I had shit loads of those, and kept feeding them to the AI!!!!!
8 ) I did indeed have a lot of the expansion stuff enabled!
9) Someone else mentioned carriers and barracks keeps the game speed up, well the AI was using lots of carriers, but not many barracks, and I was using transports to try keep the number of my ships on screen down, didn't really help unfortunately!
Is taking out all the AI's Warp Gates first a good tactic?