£400 Gaming PC need advice

*EDIT*, my friend has just informed me he already has a case so exclude that from the build.

http://www.amazon.co.uk/CiT-Vantage-Type-R-Gaming-Reader/dp/B0064LFTR8/ref=sr_1_10?ie=UTF8&qid=1400531237&sr=8-10&keywords=Computer+case

^ The case.

My friend is building a PC, his budget is around £400, the PC will be for gaming mostly and he is willing get a cheaper case if it means more money for other components although the case in the build is already pretty cheap.

I told him that he needs a better CPU and power supply, apart from that I thought the build was alright for the price but I've only ever built one pc and it's been 2 years so I'm interested in what you guys think.

The build: http://uk.pcpartpicker.com/p/2wfQf

All peripherals already purchased. We're in the UK, willing to buy from any online store.

You've almost hit the nail on the head. I can see what you're doing, and you've thought it out well. Just a few finishing touches:

http://uk.pcpartpicker.com/p/3N61m

Changed the RAM into two sticks. This will enable you to utilise dual channel memory.

Motherboard

http://www.dabs.com/products/asus-a88xm-plus-amd-fm2--a88x-ddr3-matx-9353.html?q=fm2%20asus&src=16

Has heatsinks and good features.

I believe the MSI TF 270 requires two 6 pin connectors. You can use the auxiliary molex adaptors to power the card, as the XFX 450 has only one 6 pin PCIe connector.

It's a good idea to replace the stock AMD CPU fan when you get a spare 20 quid.

Thanks for the fast response, I guess he could stretch a little further with the budget to get a more suitable PSU if you have any ideas?

*EDIT*, my friend has just informed me he already has a case so exclude that from the build.

http://www.amazon.co.uk/CiT-Vantage-Type-R-Gaming-Reader/dp/B0064LFTR8/ref=sr_1_10?ie=UTF8&qid=1400531237&sr=8-10&keywords=Computer+case

^ The case.

If you can get a Fx 6300 CPU

The XFX 450 is more than suitable. The build shouldn't consume much more than 300W, 350W at most, which leaves plenty of room for expansion. It's just a case of getting the right connectors, and they can be found for a few quid. They might come with the card. If you want to bump up the PSU, the XFX 550 is another 10 quid or so.

The build is FM2 based going AM3+ and 6300 would increase the price

Sorry for bump, but my friend has bought all the parts now, but his power supply is only 450 watts and calculators say that it's not enough, how much would the build need? We was thinking 600 watts.

450 watts is plenty.  That would should run at under 400 watts, even on full load.