AMD's Phenom II X4 955 Black Edition
by Anand Lal Shimpi on April 23, 2009 12:00 AM EST- Posted in
- CPUs
The Move to DDR3: You Can Do It
The Phenom II 955 and 945 support both DDR3 and DDR2 memory. Just a couple of months ago you could save a good amount of money by going with DDR2 over DDR3, but these days the price difference is negligible.
A good pair of 2GB DDR2-1066 sticks will set you back around $57 while a pair of 2GB DDR3-1333 modules will sell for around $60. The problem is that faster DDR3 modules usually have higher latencies associated with them. The table below shows the CAS latency of these modules in ns:
| Memory | DDR2-800 | DDR2-1066 | DDR3-1066 | DDR3-1333 | DDR3-1600 |
| Data Rate | 800MHz | 1066MHz | 1066MHz | 1333MHz | 1600MHz |
| CAS Latency | 4 | 5 | 5 | 7 | 9 |
| CAS Latency in ns | 5 ns | 4.69 ns | 4.69 ns | 5.25 ns | 5.63 ns |
From a latency perspective, DDR2 or DDR3-1066 at CL5 is your best bet. However there is a benefit from having more bandwidth; DDR3-1333 delivers 25% more bandwidth but typical DDR3-1333 modules run at CL7 which translates into 12% higher CAS latency than CL5 at 1066.
The chart below shows the performance improvement from running DDR3-1333 (7-7-7-20) vs. DDR2-1066 (5-5-5-15) on the Phenom II X4 955:
In all but two cases the improved bandwidth, but higher latency DDR3-1333 was faster - but the average performance improvement was only 2%. Some applications managed to see a 5 - 6% increase in performance but overall don’t sweat the difference.
Obviously DDR3 is going to do you more good in the long run so it’s what I’d recommend you stick to if you are building a new system. It’s lasted us a long time and we’ve enjoyed its extreme affordability, but DDR2 is finally on its way out.
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andi333 - Saturday, August 14, 2010 - link
Many online reviews written by the computer hardware. Regard it as the person seeking advice testdrives Ferrari to life when you want to buy a car for your daily needs of commuting, and he might start telling you how bad the Toyota Prius, regardless of cost or requirement. In the world of processors, this is BMW's very good that you managed to buy a very cheap price.bckolte - Wednesday, December 7, 2011 - link
i m using AMD 955 Balack Edition with Asus MotherBoard M5A78MLX is that mother board is compatible with the processor or notbecouse with this combination i got an error on bootup the system
THE CPU IS NOT SUPPORTED TO THIS PRODUCT TO DETAIL GO TO WEB SITE ASUS.COM
Now sir Help Me Or Guied me is that Motherboard is supported for AMD Pheonem 955 II Processor wht do i do with the error its a serious thing for the system or i have to ignore it
freeinstafollowersteam - Tuesday, January 24, 2017 - link
I'm guessing that he is showing the processor's actual speed during the test. The 2.8GHz speed likely is due to the i7's native ability to overclock itself via Turbo Mode (see page 4 of the article). Turbo mode tends to activate pretty much any time a load is on the CPU. But it's not really "unfair" as all i7 users get that benefit without doing anything extra, plus i7 chips still overclock far beyond that point. http://www.freeinstafollowers.info/Kickzing - Thursday, March 23, 2017 - link
AMD is really good and I really like how they run cooler than Intel. It's helped me to build my website http://getfreeinstagramfollowersteam.com so thanks AMD!