Is it worth going for a Radeon 7790 at this point (for £85)?

[Kantor]

Pemalite said:

Kantor said:
The 7870 is getting up to twice as expensive as the 7790 though.

Roughly when will the the 8000 series announcement happen?

The 8000 series was released a long time ago, OEM only. Aka. Dell machines which were re-badged 7000 series of cards.

The new series is named like: R9 290X

Yeah, the 7870 is more expensive, but it's also far more powerfull and is worth it from a price/performance perspective.
If you can find the middle ground like the 7850, go for that instead, but only if it's significantly cheaper.

Kantor said:
As for the CPU, I'll leave that for a future upgrade. Is there anything I need to be concerned about motherboard-wise (it's AM3+) or will any AMD CPU be fine? Power isn't a concern anymore, the new PSU is 750W.

That's highly dependant on the motherboard in question, in theory you could drop in any Athlon 2, Phenom 2 or FX processor.
However some motherboards have power limits, for example maximum 95w TDP CPU's, so check your motherboard on the manufacturers website to see a list of supported processors.

Also, the PSU being 750w says little about what the actual power the PSU could deliver, for example I've seen Shaw 800w PSU's literally catch on fire even under a 200-400w load, providing a brand and model name would go a long way. :P

Corsair CX750, and if I know one thing about component brands, it's "you can trust Corsair".

Will I still see benefit from a 7870 over a 7790 even if I stick with this Athlon II X4 640?