DDR2 800 versus DDR3 1333

[terminashunator]

I am planning on upgrading my current gaming computer that has a peculiar bug that prevents the ram from running at it's rated 1066 speed and will only run at 800 (2x 400).
Old Specs
Q9550 2.83GHz
4Gb DDR2 1066 5-6-6-18 2.2v (only runs 800 5-5-5-15 2v)
GTX260
Asus P5QL-Pro
500 Watt PSU
200Gb Sata HDD Boot/ 1Tb Green Data Drive

P5QL-Pro - http://www.newegg.com/Product/Product.aspx?Item=N82E16813131329

GSkill DDR2 Ram - http://www.newegg.com/Product/Product.aspx?Item=N82E16820231241
to
MSI G41M-P23 - http://www.newegg.com/Product/Product.aspx?Item=N82E16813130305

Gskill 8Gb DDR3 - http://www.newegg.com/Product/Product.aspx?Item=N82E16820231311

I want to make sure that the old bottleneck of the ram, wondering if the ~$100 upgrade will be worth it.

 

[GhislainG]

What are your expectations? You won't be able to notice the performance difference unless you run benchmarks.

 

[terminashunator]

Was hoping to see a gaming performance boost, the Q9550 and GTX260 both are decent parts, but I was hoping the upgrade of RAM would help twofold, with more capacity (4Gb->8Gb) and be faster running (DDR2->DDR3), so I was expecting a gaming performance increase in games like WoW

 

[GhislainG]

If memory utilization is very close to 4 GB, then more memory will help. DDR2-800 on a P43 motherboard will perform almost as fast as DDR3-1333 on a G41 motherboard. You can expect a performance gain of 0-3%. It will be a bit more if your system really needs more than 4 GB.

 

[terminashunator]

Darn, I was hoping it would be more pronounced than that. Gosh, that makes me wonder if it's even worth it to do the upgrade.

 

[GhislainG]

You need to understand that faster memory also has higher latencies. This article may be of interest: http://ixbtlabs.com/articles3/cpu/ddr2-800-vs-ddr3-1333.html They used slightly faster processors along with a much better motherboard than you plan on using for DDR3 memory.