First rig build and questions...

[PigeonCake]

Approximate Purchase Date: August or September 2012

Budget Range: £750 (excluding monitor which I'll buy later)

System Usage from Most to Least Important: Gaming only

Parts Not Required: keyboard, mouse, monitor, speakers

Preferred Website(s) for Parts: dabs.com

Country: UK

Parts Preferences:

CPU
Intel i5 2500K - Mfr#: BX80623I52500K = £167.98 -

GPU
Sapphire RADEON HD7870 GHz Edition OC 2GB - Mfr#: 11199-03-20G = £262.95

MOBO
Asrock Z77 Extreme4 - Mfr#: Z77 Extreme 4 = £109.99

RAM
RAM: Corsair Vengeance 8GB: 2 x 4 GB - Mfr#: CMZ8GX3M2A1600C9R = £39.99

HDD
Seagate Barracuda 1 TB - Mfr#: ST1000DM003 = £64.99

PSU
Corsair Enthusiast Series TX750 V2 Power supply - 750 Watt - Mfr#: CMPSU-750TXV2UK = £79.99

CASE
XIGMATEK Asgard - Mfr#: CPC-T45UB-U01 = £29.98

MONITOR
Unsure. Something with 2ms to 5ms response time and refresh at 120hz.


Overclocking:
Yes, once it's up and running.

SLI or Crossfire:
Yes (not to begin with but within a few months I'd like to stick another 7870 on there.

Monitor Resolution:
1920x1080 at 120hz.



Additional Comments:
Right, I've posted a few threads on Toms in the last few weeks and have now discovered this part of the forum which might be a better place to keep all my questions in one place.

First off...

PSU
Much talk about buying a good one so I've gone for a Corsair 750W model, but would it make any difference if I bought an 850W? I might not need it now but if I did in the future I might as well if it makes no difference to the amount of power it draws from the wall, which I'm told it doesn't? Or does it...?

Still on the PSU, is there anyway of doing a circuit diagram of my components to make sure I'm going to have the right amount of plugs and connections. I've just pulled the corsair model out of the air without any real knowledge as to if it's going to work with all my components.

FANS
Do I need to buy fans for this? Or perhaps a CPU cooling block?

CASE
Might it be better to get a E-ATX case to make sure any future added cooling units and fans will fit?

MONITOR
This won't be in my initial build but I want a 120hz monitor. Is there a model someone knows about that will definitely give me 120hz with my GPU. I've read a few forums where people have got a 120hz monitor but can only run it at 60hz on there system.

RAM
Whats the difference between this 8GB Corsair RAM and this 8GB Corsair RAM?

 

[smorizio]

looks to be the same ram..just every one wants black so there paying more for color. there are a few things with cases and case sizes. yes one is fans how many the case has but it also airflow. most good gaming cases now have one front fan that pulls air int ot the case and two fans to blow the hot air out. they also have the top of the case grilled to let hot air flow up out of the case like a rad. the smaller a case is the harder it is for wire management and having a little extra room for longer video cards or taller or big fans for the cpu. i got myself an antec one gaming case..nice little case and a asus 7zz sabertooth mb. it not a bad case i would have gone to a larger cosair 300r so i could hid more of my power supply cables. looks like i have a face hugger living inside my case. the intel stock heat sink is ok for normal web and light gaming. if your going to be gaming for a few hours on the pc then pcik up a 212 heatsink.. it a little larger then the stock heat sink in size and hight.. up under load it going to keep your cpu in the 50-60c range. with new cpu the hotter they get the slower they start going..they throttle back to keep them-self from hitting there burnout temp. also as they run hotter they start pulling more power from the mb. as some point the cpu or the mb chip get to hot and start locking up. (why high end gaming rigs use water and lgn).
with a power supply look at online testing reports like hardcops forum where they load test power supplys. also look at online video from power supply vendors cosair vp of sales have made a few good ones for new buyers on what makes a good power supply and how to size a power supply. you dont want to put in a 1000w ps on a 300w load. that called under loading a ps. most times your trying to be in the 60-70 percent of the power supply rated value. as you get closer to the max value the power supply has to work harder...more heat and also if the parts or design of the ps is off then under a heavy load it can fail and fail bad.
http://www.youtube.com/watch?v=wK8p7dGSdmo