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CPUs have up to Hyper Transports 4000MHz but motherboard only 2600mhz?

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June 17, 2008 9:35:42 PM

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?
June 18, 2008 4:29:15 AM

i thinks its 2000 not 4000

to be honest i have never used a amd quad - duals is 2000 and 2600 is oc
June 18, 2008 4:54:21 AM

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.
a b à CPUs
June 18, 2008 8:40:32 AM

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

AM2 = 2000Mhz or less

AM2+ = 2600Mhz or less
a c 102 à CPUs
a b V Motherboard
June 18, 2008 2:36:55 PM

ahtze said:
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?


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.
a c 117 à CPUs
a b V Motherboard
June 18, 2008 3:30:15 PM

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
October 15, 2011 7:13:39 PM

The actual CPU is only rated for 4000MT/s HT (2000mhz * 2 [HT is bi-directional] = 4000MT/s). However, the motherboard's chipset, itself, is rated for 2600mhz (5200MT/s).
a b à CPUs
a b V Motherboard
October 15, 2011 9:26:30 PM

This topic has been closed by Mousemonkey
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