Per Jessen wrote:
Not sure about that - AFAICT, it's exactly the same technology. (I
haven't done in exhaustive tests though).
----
Supposedly 'Very' different (I hope)...
1) You can't turn it off in the BIOS
2) claim of benefit from increased cache (FALSE),
(have older 2x2 Dual Core machine with 4MBxL2 Cache/Dual core.
If you only use 1 Core/CPU, that 4MB L2 cache/Core)
New machine with 1 Quad core (Dual core CPU's are too slow
to use memory faster than 800MHz -- only Quad cores go up to Quick
Connect Speeds that will support fastest memory of 1333MHz (even if
you only have 1 CPU). So you are 'encouraged' to go with Quad over
2x2Dual. Quad has 8MB L3 Cache, w/256K dedicated L2/Core. So
with HT 128K/thread. To get 2 Cores, they'll get 256K-L2 ea, +
8MB L3 shared. So about 3.125%more memory! WOW ea!...(though the
bandwidth for the fast core processors to main memory can be 2x faster).
3) Here's possible benefit: they've added more parallel resources to
each core -- so each thread can possibly get more done than the
old threads -- but this is only a maybe depending on workload.
The biggest cool thing about Nehelam is power savings -- they implemented
Celeron's power-step tech in a big way. Quiescent cores crank down their
clocks independently to about 60% of top speed and have efficient sleep
states (I think some cores can be halted, but not sure). Some of their
processors have a 'turbo mode', which will some small amount faster speed
than the speed on the chip label (does that mean the turbo chips are really
faster rated chips...you tell me), BUT if fewer cores are used -- say only
2/4, the turbo boost can be a small amount greater (don't have access
(don't know if any is published). If one was to go from their marketing
graphs (HAHAHAHAHA), Turbo for 4 cores is about 10 more, and if only 2/4
cores are running, it's an additional 10%. So marketing hype/reality,
might mean 1-3% faster?
I will say this much -- @ idle, w/8 disks (it's a server, so built-in GPU
with 8MB shared memory, if you aren't going headless) -- with dual/redundant
PS, it uses 157W. (1-PS, slightly more efficient at 146W). Major power
savings with possible big increases in speed. But you can't turn off HT
as in previous machines (at least not in the one I've had access to).
That power consumption is less than half their older Workstation model (though an idle graphics card still sucks quite a bit of useless ergs
(stupid Nvidia)..
Oblig SA content: When I ran 100 msgs through my filters (that connect to
spamd, but that uses net), the MHz immediately jumped from ~1596 up to 2300 on
each of the '8' HT cores...so might be perfect for a server that gets sporadic
loads! ;-)
-linda
