Physically speaking, the 940-pin socket AM2 processor
is nearly identical to the previous 939-pin Athlon64 generation, yet the way
heatsinks attach to it is different in one very significant aspect;
a new heatsink retention frame.
heatsink retention frame attaches
to the ASRock AM2V890-VSTA motherboard via four holes, rather
than two like the previous generation K8 heatsink retention frames relied upon. The socket
AM2 heatsink retention frame and metal backplate are not compatible with the previous K8 socket 754/939/940
heatsink retention frame and metal back plates, and vice-versa. This one
small change has effectively retired hundreds of different socket 754/939/940 K8 heatsinks
since most pre-AM2 K8 heatsinks are not compatible with the new
four-post heatsink retention frame. Bummer.
motherboards like the ASRock AM2V890-VSTA ship with the new AM2 heatsink retention frame
pre-installed, so you don't need to worry about that. What you
will need to be aware of is that
existing K8 heatsinks that screw directly into the two-post metal backplate
of the socket 754/939/940 series are not usable with the socket AM2 retention
module, because its four-posts are positioned differently.
Unfortunately, most K8 heatsinks that
use the two-posts the high-end, heavy copper coolers that offer the best performance
qualities. The weight of these expensive enthusiast level heatsinks dictated a
firmer attachment method than the plastic tabs of the old retention frame, and
sadly their useful life is now over.
K8 heatsinks like the Zalman CNPS9500 AM2 and AMD retail AVC Z7U741001 heatsink that clip onto
the socket 754/939/940 heatsink retention frame center tabs will continue to
be compatible with the socket AM2 heatsink retention frame. The center tabs
survived the transition to socket AM2, alongside with a new type of four-post
socket 478-like integrated clip points. Existing K8 heatsinks which use a cam-lock
to apply pressure on the spring clip after it has been attached to the
retention frame tab will also work with the ASRock
Three tab K8 heatsink clips should also work with AM2. The socket AM2
standard has also introduced Pulse Width Modulation (PWM) fan speed control, as
identified by four-pin fan power cords. The ASRock AM2V890-VSTA motherboard ascribes to
this standard, so either a 4-pin PWM fan or standard 3-pin fan
can be used to cool the chip. With an AVC Z7U741001 heatsink strapped onto the AMD Athlon64
FX-62 processor, we
set about overclocking the ASRock AM2V890-VSTA and its VIA K8T890 chipset for all its worth...