I have a comp that can run GTA 5 on all high settings at 40-45 FPS. The question is, can I run Fallout 4 above 30 FPS on High settings? I have a Power color 7850 HD 2gb, an I7 processor and 16 gb of ram.

Probably? Who knows. We are yet to receive official requirements from Bethesda. Also, your RAM and CPU contribute to FPS and general game performance and despite popular belief, GTA V ins't that hard to run. Considering the last gen could run the game at a nice quality..

Just wait for the specs to be released or wait for the game to be released.

High settings would seem like a fair guess for now. Very doubtful the 7850 could do Ultra/Max. Just gotta wait and see the reqs whenever they come out.

they have not released system requirements yet, so no one knows. based on the graphics in the footage shown maybe, but there are other factors that go into that.

I'm a little put out that Bethesda has not given any solid requirements yet. I know they are supposedly bug smashing and that might optimize performance, but for those folks looking to add a new GPU or some extra RAM, it would be nice to have something more solid than game site and fan theories to go on. I'm pretty comfortable with my own specs, but I sure would like to make sure I'm not underestimating anything. We only have a about 3 1/2 months left. Some folks have to save up some bottlecaps in order to buy both the game and any hardware upgrades that they might suddenly find themselves needing.

I think it is best to wait until it is closer to release since at the moment the specs can change since this is the time they are doing the fine tuning phase.

I think at a minimum they shouldn't take pre-orders for the PC version of the game until they have released the system specs. I expect it'll be easy enough to cancel your pre-order if it turns out your computer won't run it well, but it's still kind of bad form, IMO, to offer the game for sale without letting customers know how much PC horsepower they're going to need.

I don't think the performance should be too far off those of Skyrim since they're using the same engine with tweaks, right?

There's no pressure on Bethesda to release requirements until the box art needs to be locked down ready to print.

While they are polishing, and the game may always be 'subject to change', why commit?

It's not as if pre-orders can't be cancelled or a decision to pre-order or buy at launch can't be made.

Past behaviour is the best indicator of future behaviour.

• Fallout 3 announced specs on 9th October ahead of 28th October launch (19 days)
• Skyrim announced specs on 25th October ahead of 11th November launch (17 days)

So expect system requirements for Fallout 4 to be released between 17-19 days ahead of launch.

Those days are heading to the weekend, so my guess is:

System requirements for Fallout 4 will be released on Thursday 22nd October (19 days before launch, just as Fallout 3).

Then you will know.

They're introducing a lot of new lighting effects though, so it's hard to say how that will impact performance. Changes in scripting implementation could also have a big effect on CPU performance.

Yeah, that's true I guess. My rig is getting kinda old, but it still runs Skyrim fully modded nicely, so I'm hopeful I won't have to upgrade.

Recently upgraded my cup just for this.
Specs:
Cpu Fx-6300
gpu hd Radeon 7870
DDR 3 1866 ram 8 GBP
And of course a decent motherboard though of the micro atx form factor. Needless to say I'm good. Plays Rome total war 2 at extreme.