Hello. I am confused. I look at the AMD phenom but there's some CPU that have 4000mhz, 3800mhz but then all the motherboards I see only support up to 2600mhz? What's happening?

i thinks its 2000 not 4000

to be honest i have never used a amd quad - duals is 2000 and 2600 is oc

The AM2+ motherboards are just motherboards that provide easy support for quads while AMD transitions to the AM3s. I'm sure they haven't yet worked out the kinks on these higher HT speeds. But I would love to see what a phenom can do paired with a much higher HT speed, not sure if its going to be a mega performance increase but it could be significant.

can't be 4000, if Phenom Black B3 is 2600... or so...

AM2 = 2000Mhz or less

AM2+ = 2600Mhz or less

The discrepancy is that HyperTransport is a DDR interface and that some vendors cite the link clock speed and some cite the effective data rate. The full HT 3.0 spec is for a clock speed of 2600 MHz DDR, giving an effective data rate of 5200 MT/sec. The fastest Phenom has a 2000 MHz DDR HT link for an effective 4000 MT/sec.

HT 1

* 200 MHz = 400 MT/s = 800 MB/s
* 400 MHz = 800 MT/s
* 600 MHz = 1,200 MT/s
* 800 MHz = 1,600 MT/s

HT 2

* 1,000 MHz = 2,000 MT/s
* 1,200 MHz = 2,400 MT/s
* 1,400 MHz = 2,800 MT/s

HT 3

* 1,800 MHz = 3,600 MT/s
* 2,000 MHz = 4,000 MT/s
* 2,400 MHz = 4,800 MT/s
* 2,600 MHz = 5,200 MT/s


A single 16-bit HyperTransport link has 2 unidirectional channels. The clock rate (MHz) is 'doubled' per clock cycle (like DDR ram - 'double data rate'). It is not uncommon to see something like 5,200MHz (2,600MHz x 2) when 5,200MT/s would be correct.

MT/s stands for Mega Transfers per Second, or millions of transfers per second

Check this out by urself. AMD Phenom 9850. have 4000mhz HT
http://www.newegg.com/Product/Prod [...] 6819103249

AMD Phenom 9750 have 3600MHz HT
http://www.newegg.com/Product/Prod [...] 6819103250

Click on specification