Best suitable motherboard and build?

[xEminX]

Okay so currently I have the following (the essential ones):
Core2Quad Q9550
4x2GB DDR2 400Mhz Ram
GTX 560 Ti
A motherboard with PCI Express 1.3 (Yeah cant get card's full potential yet)

So I was thinking of going for:
i5 2500k
Same card
Asus P8Z68 motherboard
4x2 GB DDR3 1600 MHz Ram

Seems too much of investment, basically I want it for gaming for the most...So I got some questions...:
First of all....is it worth upgrading? I was wondering how much performance increase I can get...Any idea?
Also, according to those requirements, can anyone suggest me a suitable motherboard? I don't want an expensive board, just good enough that fulfills those, someone told me about P8Z68...just wanna know suggesstions.
I'll be using a single nVidia card by the way and will require 4 RAM slots...Someone said that 8 GB DDR3 1600/2000MHz ram is enough for gaming, or should I go for 16 GB? I want the best performance out of decent cost.. Thanks.

 

[jaquith]

The i5-2500K is the de facto best CPU for the money CPU, it's best to get a 2x4GB DDR3-1600 CAS 8 or CAS 9, and for OC'ing MOBO:
P67 - ASUS P8P67 PRO (REV 3.1)
Z68 - ASUS P8Z68-V PRO or P8Z68-V PRO/GEN3

ANS:
If your current MOBO has 16 PCIe lanes to the (1) GPU then even at 250MB/s per lane there's no bottleneck. The Quad core doesn't suck, and depending on 'what game(s)' anywhere from a 0FPS increase to 8~10FPS the last comparisons I recall.

The Sandy Bridge 'sweet spot' for Gaming is 2x4GB DDR3-1600 CAS 8 or CAS 9.

MOBO's assuming the plan is to OC you want 12 Phases or more to the CPU and a good HSF e.g. Thermaltake Frio.

The ASUS P8P67 PRO (REV 3.1) is the best bang for the buck for gaming and OC - $160 http://www.newegg.com/Product/Product.aspx?Item=N82E16813131771

 

[xEminX]

Well, for beginners, I wasn't lookiong for overclock any component yet if I buy them, but I may do it in future..
My current Mobo has 8 gbps bandwidth or something in terms of graphics (I suppose thats what was written)

Regarding the mobo, I'd like to have onboard graphics just in case my card is damaged somehow (experienced it before)...

Also, regarding RAM, I was gonna go for Corsair, I want an overall good one and was trying to decide between Vengeance and XMS3, Vengeance looked epic and had good specs as well, should I go for that?

Thanks.

 

[jaquith]

In OC'ing the LGA 1155 Sandy Bridge it's not at all complex, so get a good MOBO from day 1 if getting a 'K' CPU. You only want 1.50v RAM with Sandy Bridge, and for the money get DDR3-1600 CAS 8/9 2x4GB kit(s); e.g. CMZ8GX3M2A1600C9B