Help..Problem Before Finishing my build

[Ironman01]

Ok so I had my build ready to order at the end of this week when I get my check :
Don't need a keyboard/mouse/monitor
Mainly for gaming and multimedia
Budget is 900-1100

SAMSUNG Black 22X DVD Burner Black SATA Model SH-S223B - OEM
http://www.newegg.com/Product/Product.aspx?Item=N82E16827151187 $31.99

SAMSUNG Spinpoint F1 HD753LJ 750GB 7200 RPM SATA 3.0Gb/s 3.5" Hard Drive - OEM
http://www.newegg.com/Product/Product.aspx?Item=N82E16822152100 $64.99

CORSAIR CMPSU-750TX 750W ATX12V / EPS12V SLI Ready CrossFire Ready 80 PLUS Certified
http://www.newegg.com/Product/Product.aspx?Item=N82E16817139006 $119.99

COOLER MASTER RC-690
COOLER MASTER Intel Core i5 & Intel Core i7 compatible RR-B10-212P-GP 120mm ....
http://www.newegg.com/Product/ComboDealDetails.aspx?ItemList=Combo.259675 $89.98

SAPPHIRE Vapor-X 100269VXLE Radeon HD 4890 1G
G.SKILL 4GB (2 x 2GB) 240-Pin DDR3 SDRAM DDR3 1600 (PC3 12800)
http://www.newegg.com/Product/ComboDealDetails.aspx?ItemList=Combo.256446 $260.98

Intel Core i5-750 Lynnfield 2.66GHz LGA 1156 95W Quad-Core
ASUS P7P55D EVO LGA 1156 Intel P55 ATX Intel Motherboard
http://www.newegg.com/Product/ComboDealDetails.aspx?ItemList=Combo.259877 $359.98

Total w/ shipping Before MIR $958.88
Total w/shipping after MIR $918.88

Possibly changing the 4890 for the 5850 now that I know its only 260 !!
Now my problem is I just realized I can pick up a i7 920 for 200 dollars(micro-center) same price as the i5 and get a X58 mother for cheap like a ASRock X58 Extreme LGA 1366 Intel X58 ATX Intel Motherboard instead of the p55
http://www.newegg.com/Product/Product.aspx?Item=N82E16813157163

Should I change to the i7 and the x58 motherboard?? What is the real difference ? I'm really confused on this,

 

[WR2]

It's a good problem to have because each choice gives you a very good performing system.

For a single card system there is basically no difference. A slight advantage maybe to the i7 860 in turbo boost mode.

For a multi-card system the dual x16 PCI-e lanes of the X58 have a performance edge over the dual x8 PCI-e lanes of the P55.
This AnandTech article helps explain how much difference there is using dual video cards. ATI HD 5870 Scaling Performance: X58 vs P55 Showdown
I know the article says 5870 scaling but its also generally true for the 5850.
The differences in dual card operations are small enough to not be noticeable, IMO, since both i7 920/X58 and i7 860/P55 kick some serious ass.

 

[Ironman01]

It's a good problem to have because each choice gives you a very good performing system.

For a single card system there is basically no difference. A slight advantage maybe to the i7 860 in turbo boost mode.

For a multi-card system the dual x16 PCI-e lanes of the X58 have a performance edge over the dual x8 PCI-e lanes of the P55.
This AnandTech article helps explain how much difference there is using dual video cards. ATI HD 5870 Scaling Performance: X58 vs P55 Showdown
I know the article says 5870 scaling but its also generally true for the 5850.
The differences in dual card operations are small enough to not be noticeable, IMO, since both i7 920/X58 and i7 860/P55 kick some serious ass.

I see what you are seeing....But it wouldnt be the i7 920/X58 and i5/p55 .....so in that scenario what do you think?

 

[WR2]

If you're asking about the $200 i7 920 vs $200 i5 750 vs $290 i7 860
Asrock X58 $205 vs Asus P7P55D PRO $170
The the i7 920/X58 is only $35 difference plus $45 extra in RAM (only 4GB in P55 but 6GB in X58)
You'd want the i7 920/X58 over the i5 750/P55 if the price is close enough for you.

 

[balanovich]

Do you know that the I7 920 at 200$ is available only for in store pick-ups ?

Considering the very very slight difference in performance and the price difference for the ram and mobo... I'd stick with the 750.

The i5 750 has the advantage of overclocking itself when only one or two cores are strained witch will give you a small boost... Unless you're going to overclock. In witch case the I5 loses an advantage.(but would still be my humble choice)

And you probably want to CrossFire is you are to fully take advantage of an overclocked I7 920 (I5 too actually)