Which of these gaming PCs should I buy?

for me either PC1 or PC2, I'm looking at the RAM/GRAPHICS/HDD... Might go for PC2, of course it would render gaming and browsing at the same time, you'll have enough memory for it :)

here is a kicka*s system for round the same cash with the new 8 core amd

http://www.ebay.co.uk/itm/NEW-GAMING-PC-AMD-FX8-8350-8-Core-4-0Ghz-x8-16Gb-DDR3-RAM-1TB-SATA-HDD-240Gb-SSD-/251188369753?pt=UK_Computing_DesktopPCs&hash=item3a7bfe5959&_uhb=1

I will prefer PC2. A friend of mine has a very similar configuration. But this is only my choice. PC number three is not bad too.

third one is the fastest but it will struggle with many current games, I honestly cant recommend any of those systems for the money.

while you don't want to build, you are really missing out if you don't.

All 3 are just horrible deals with the second one being the 100% worst

The FX 6 and 4 core chips are really just 3 and 2 core chips as AMD now uses a core module design (basically a better implementation of what would be intel's hyperthreading, with the main difference being the extra integer unit. but the majority of the components in the core module are shared so you do not get 99-100% performance scaling like with a traditional multicore (like what you would get in the core i5 (the core i5 also has significantly better single threaded performance which is most beneficial when gaming)

for example here is core module performance vs 4 true cores on the same chip, (the FX 8 core offers up to 4 threads to not be shared if 1 thread per core module)

http://www.extremetech.com/computing/138394-amds-fx-8350-analyzed-does-piledriver-deliver-where-bulldozer-fell-short/1

the performance drop when 2 threads are on one core module get even work if you are running 2 entirely different CPU intensive applications on the same module as you no longer have a have the caching working efficiently (basically, you can lose more than half of your CPU performance when multitasking while using core modules instead of traditional CPU cores where performance related components are not being shared.

The videocard that you get is a lower end gaming videocard for all of the systems offered, and for that price, you really should be getting a higher end GPU (eg at least a radeon 7850 or geforce 660ti)