65w vs 45w Intel Xeons

ChrisOlver · 24th February 2008

Has anyone found any major increase in performance with the new 45w Xeons?

I have found a nice Tyan motherboard which takes dual quad 65ws but doesn't support the 45w according to their website but the pricing of the board makes it around £100 less than the 45w compatible motherboard. While that may sound like much extra their is not much point in paying it if the 45w don't make allot of difference.

These will be running game servers so just think about badly coded software which cant make use of multiple processors (you have to set processor core infinity on each instance them) to get best usage on the server.

Hope to hear your thoughts,

-Chris

[inx]Olly · 24th February 2008

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aXeR · 24th February 2008

Game playing wise i.e. fps, an identically clocked 45w chip worked out to be about 5-7% quicker. That was from a very thorough article I read spanning multiple popular games and video benchmarks.

To be honest though, the gain++ is from the decreased power consumption thus cooler running temperatures which were much more significant.

ChrisOlver · 24th February 2008

Ah less power heh? Say in amp wise, how much difference does it really make? 0.1 amp? 0.05 amp per chip?

-Chris

SynergyWorks · 25th February 2008

Well from an electrical point of view - 20Watts at 230Volts = 0.087A

Cyberprog · 25th February 2008

Yes, but the chips aren't run at 230V, they're running at 5V or 12V I believe...

SynergyWorks · 25th February 2008

Quote:

Originally Posted by Cyberprog

Yes, but the chips aren't run at 230V, they're running at 5V or 12V I believe...

Hence "from an electrical point of view". I was hoping somebody smart would work it out properly

othellotech · 25th February 2008

AFAIUI they run @ 3.3v as

W=V*I
65=5*11 (std chip)
45=3.3*13.6 (new chip)
so they actually consume *more* power :P

however they run colder, so are more suited to an aircon'd environment, and in theory require less from the fans (and fans use more power than the cpu )

HTH

aXeR · 25th February 2008

There's less leak though Rob so the chips are more energy efficient due to the change in materials used.

edb49 · 25th February 2008

Quote:

Originally Posted by Cyberprog

Yes, but the chips aren't run at 230V, they're running at 5V or 12V I believe...

Huh?! Your PSU does all the AC-DC and voltage stepping. You need at least another 20 watts going into the server, which as Rob has worked out correctly.

Factors to add in:
- PF
- PSU efficiency at delivering 3.3v or whatever is needed
- CPU won't always be running at 100%

Karl · 25th February 2008

Just as an FYI, PSU delivers 3.3v, but the VRMs step it down again to about 1.6-1.7V depending on the part of the chip it's going to.

aXeR · 25th February 2008

Another note is that to consider is that the new 45nm breed CPU's are optimised much better to handle tasks when 100% CPU usage is not required.

Older Intel chips would drop the CPU multi when the CPU was idling and bump it up when there was any workload. New design can turn individual parts of the CPU on when its workload requires additional ooomph, seems really clever

JamesSykes · 25th February 2008

Quote:

Originally Posted by [inx]Olly

Lol, amen

In my day (LOLOLOL) I remember (just about) getting 100 counterstrike players concurrent on a Dual P3 1Ghz. When TF2 came out I threw up a server for a few weeks and I just about got 24 players on my dual xeon 3ghz

[inx]Olly · 25th February 2008

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ChrisOlver · 25th February 2008

I know the feeling with TF2

Well in simple terms :P Are the 45w processors worth the extra money linked with it?

-Chris