4870 or 4890?

[kwarde]

Assumptions:
1. 4870 ~$145, 4890 ~4$190
2. Buying one card now but want ability to crossfire down the road
3. looks like 2 x 4870s require a 750W PSU and 2 x 4890 will require a 850W PSU
i have a 22 inch 1080P display

So...
A. Is that PSU requirements assessment correct?
B. How much better is the 4890 than the 4870
C. Given my build, will i tell the difference between 4870 and 4890
D. If that $ and PSU assessment is correct i will have to spend an extra ~$45 for the 4890 PLUS $ difference for larger PSU... is that correct?

Thanks, build info below from previous post.

APPROXIMATE PURCHASE DATE: Next week or two
BUDGET RANGE: $800-$1000

SYSTEM USAGE FROM MOST TO LEAST IMPORTANT: Primarily for gaming but do not want to spend the bank. Company of Heros, other RTS down the road, occasional shooter

PARTS NOT REQUIRED: All except monitor
PREFERRED WEBSITE(S) FOR PARTS: newegg.com

PARTS PREFERENCES: Thinking AMD x3 720 BE

OVERCLOCKING: Maybe SLI OR CROSSFIRE: Maybe

MONITOR RESOLUTION: 1080P 22”

ADDITIONAL COMMENTS: New to building computer. Would like some performance for gaming but not cutting edge. I may play with overclocking down the road but likely need to stick to moderate over clocking and a motherboard that helps noobs overclock.

AMD Phenom II X3 720 2.8GHz 3 x 512KB L2 Cache 6MB L3 Cache Socket AM3 95W Triple-Core Black Processor - Retail
http://www.newegg.com/Product/Prod [...] 6819103649 $119.00

Antec Three Hundred Illusion Black Steel ATX Mid Tower Computer Case - Retail
http://www.newegg.com/Product/Prod [...] 6811129066
Or Scout Case
http://www.newegg.com/Product/Prod [...] 6811119196

Microsoft Windows Vista Home Premium SP1 64-bit for System Builders w/ Tech Guarantee - OEM (Includes free Windows 7 updrade coupon)
http://www.newegg.com/Product/Prod [...] 6832116677

GIGABYTE GA-MA790GPT-UD3H AM3 AMD 790GX HDMI ATX AMD Motherboard - Retail
http://www.newegg.com/Product/Prod [...] 6813128398 $114.99

G.SKILL Ripjaws Series 4GB (2 x 2GB) 240-Pin DDR3 SDRAM DDR3 1600 (PC3 12800) Desktop Memory Model F3-12800CL7D-4GBRH - Retail
http://www.newegg.com/Product/Prod [...] 6820231279 $94.99

SAMSUNG Spinpoint F3 HD502HJ 500GB 7200 RPM 16MB Cache SATA 3.0Gb/s 3.5" Internal Hard Drive - OEM
http://www.newegg.com/Product/Prod [...] 6822152181 $54.99

SAMSUNG DVD Burner Black SATA Model SH-S223L LightScribe Support - OEM
http://www.newegg.com/Product/Prod [...] 6827151188 $31.99

Antec TruePower New TP-750 750W Continuous Power ATX12V V2.3 / EPS12V V2.91 SLI Certified CrossFire Ready 80 PLUS BRONZE Certified Active PFC "compatible with Core i7" Power Supply - Retail

 

[hunter315]

A good 750 like the 750TX will run 2 4890s easily, where did you get the 850 requirement from?

The performance difference is about 10%, not huge but still noticeable in most cases and it is unlikely to be bottlenecked by your processor at that resolution.

 

[kwarde]

Got the 850 W from some online calculators...are they fudging high on their estimates?

 

[Bluescreendeath]

I think the 4890 xtreme overclocked (900MHz to almost 1GHz) will require 850watt PSUs for SLi to be on the safe side.

Regular and slightly overclocked 4890s use the same amount of power as the 4870.

I'd say get the 4870 now, then wait for dx11 cards. (4890 is about 15%-20% better than the 4870)

 

[grieve]

**Just another option to throw around**

Get a 4870x2 and wait for the prices of the DX11 cards to come down and some games to be released. (1 year'ish)
then sell the 4870x2 and get two DX11's.