So you are agreeing, yet disagreeing with me.

The GDDR5 Ram on a PC is just a cache! A cache dedicated to the GPU.

For example, take AMD's Cayman architecture, the L1 and L2 caches in the GPU were unchanged over Cypress, but AMD still threw twice as many Tessellators in the GPU. - That's allot of geometry information which can't fit in those tiny caches, so where is the Geometry supposed to go? Back to a larger but slower cache, enter: GDDR5 memory.

AMD and nVidia call the memory next to a GPU an "Off-Chip Buffer" for a reason, it's a cache.
https://en.wikipedia.org/wiki/Cache_%28computing%29

And then you contradict your entire post with this simple line.

That's the point of a cache hierachy's on the PC, so you don't have to.

Why do you think all memories in a PC go from Slowest+Largest to Fastest+Smallest? It's to hide latency and bandwidth deficits in all stages of memory retrieval whilst keeping costs down so you don't need 16Gb of L1 cache each on the GPU and CPU.
Remember, GDDR5 is pitifully slow compared to L1 and L2 caches.

The need for 8Gb of GDDR5 on a GPU isn't needed now or in the immediate future on the PC, main graphics tasks will be stored in the current GPU memory  with excess data in system memory which will get swapped into the GDDR5 on demand, in-fact, that's how it's always worked with PC graphics, even before the AGP bus or DDR was ever invented.

And by the time that GPU's will need 8Gb of GDDR5, JEDEC should ratify the GDDR6 standard anyway, making the PC a generation ahead in memory technology. (And is due out next year.)

Do you even read, I told you that it wasn't just a cache. Any kind of memory is cache, like seriously did even read it. I thought we were talking about building a ps4 today, next year sure. Three years from now, yeah in my sleep, your point. Of course cpu cache is a lot faster, you miss my point entirely. I was drawing comparison between graphics tasks which are gpu based and video memory (speed and latency) optimized.

And off course it's not just faster beats smaller. I took the extreme to make a point, at no point did I say that the smaller the memory the better. I was stretching the importance of gddr5 which you referred to as being just cache because you have a computer with 7gb of dedicated ddr5 memory. Of course not all task require high bandwith, which brings me to this point. IF you knew as much as I did you would have understood what I was alluding to. On pc you're memory is split between your regular ddr3 and gddr5 which leads to memory fragmentation and other inefficiencies. My point was and still is that a game build to run on high bandwith will not perform well on a computer of similar specs on bc with less ram. Your answer was, oh it's just cache. Than you quoted me saying that it is not JUST cache. To say it better cache refers to anything holding data, when you say that it is JUST cache is like saying that ram is just like hard drive, which I hope you can tell the difference.

Hear is a child's allusion for you. There are several types of fruits, but not all fruits are the same. They might overlap in some areas, but that does not make them the same. Graphics memory, hard drive, cpu cache are all cache but they are not just cache. You must be able to seperate them. they are not completely interchangeable.

Read before you plead, then learn before you speak.

You sound really ignorant, you dont seem to even understand english. When someone says that something is not just something, that does not mean it is not it at all. How old are you? And I am not even trying to insult you or anything, it's a fun discussion but seriously. You either dont read or always want to be right. Oh and one last time RAM IS NOT JUST CACHE. There are more dynamics involved to the matter.

Derogatory, condescending defensive comments aside and the fact you keep contradicting yourself...

My entire point is you don't need to build a PS4 replica, you can achieve the same results (Or better) with different hardware off the shelf today, the rest, I'm not even going to bother repeating myself with.

CPU - 100  Try  $170. Intel i5 3350. Don't even try putting in a cheaper AMD for a measly $20-30  (which would sytill be >$100)

GPU - 150 No. Try again. $200 Geforce GTX 660

Mobo - 50 Fair but you could go a little cheaper but I wouldn't

RAM - 50 I'll go with that.

Case - 50 I'll go with this as well (if you like ugly).

= 400 $520

There you go.

OS can be easily *borrowed*. He wants to do it right not be a pirate. OS-$100 or if you go Linux then it could be $0 but tons of fucking headache.

You can take power supply and hard drive/solid state drive from your previous build mom. Can he borrow his mom's PS4 or use the PSU and BRD from his old PS3? Nope sooo... PSU ->$50 bucks (don't chince out on your PSU and $50 is still cheap), BRD-$50, Since you should be able to use the existing HDD from your old PS3 I'll give ya the HDD could be from an old build. But, I'm guessing that this would be a total new build.

So grand total = $620-720.

And to be honest this wouldn''t really do it for ya. You'd never get the PC 'advantage' of better visuals because you'd be setting all your GFX card settings to performance and your in game settings would be on medium maybe high and you'd get 30FPS at best on any of the next crop of games. You'd be looking to upgrade in a year or two at best. People who spend <$1000 are the ones screaming that people playing CoD and BF are hacking because their rigs don't run as well. Also you don't get the level of optimization you get on a console. PCs achieve their level of performance and fidelity through brute force and having a wimpy ass PC aint gonna do that.