Solved

Will a Pentium D 955 work in a Dell PowerEdge 830

Posted on 2009-04-10
17
1,949 Views
Last Modified: 2013-12-10
Ive been a bit busy to look this up myself so Im going to throw this on here. I have a Dell PowerEdge 830 with a Pentium D 830 in it. I wanted to test out some 64-bit virtualization technologies on here, but I just discovered that this processor does not support Intel VT. I do however have a Pentium Extreme Edition 955 that is not being used which does support Intel VT. Will this processor work in my server?
0
Comment
Question by:andrew_aj1
  • 6
  • 6
  • 4
  • +1
17 Comments
 
LVL 17

Assisted Solution

by:Nik
Nik earned 166 total points
ID: 24117692
Both processors are for LGA775 socket. You'll be able to fit the new processor in the socket.
Pentium 955 has a faster FSB, but that's limited by the MBO. You'll use as much as MBO lets you. Power consumption is the same for both processors.
You should give it a try IMO..
0
 
LVL 26

Assisted Solution

by:PCBONEZ
PCBONEZ earned 166 total points
ID: 24119611
No that won't -officially- work.

The PowerEdge 830 only -officially- supports processor with an 800MHz FSB. [Front Side Bus]
http://www.dell.com/downloads/global/products/pedge/en/830_brief.pdf

Pentium D 955 has a 1066MHz FSB.

Technically the chipset supports 1066MHz FSB but as Dell doesn't it's unlikely the BIOS will recognize a CPU that uses a 1066MHz FSB.
0
 
LVL 70

Accepted Solution

by:
garycase earned 168 total points
ID: 24120025
As PCBonez noted, the 955 is not officially supported.

What would most likely happen if you install it is that it would simply run at 2.60GHz [The 800MHz FSB is 800/1066th of the expected bus speed;  the multiplier wouldn't change; so the effective speed would be 3.46 * (800/1066)].
0
 
LVL 17

Expert Comment

by:Nik
ID: 24120878
But, nothing bad would happen if he tries it, right?
0
 
LVL 70

Expert Comment

by:garycase
ID: 24120909
No, it's still a 9xx series CPU (which is supported in its 800MHz versions).   It would almost certainly just run at 2.6GHz, as I noted above.
0
 
LVL 26

Expert Comment

by:PCBONEZ
ID: 24121136
One problem would/could be that the PowerEdge 830 doesn't have support for the 1066MHz speed at all.
[No divider/multiplier for the clock.]

The other problem is as Dell had no intentions to support that CPU the microcode in the BIOS won't have the ID for it and won't know what it's settings are. That means RAM and possibly CPU voltage settings settings may have to be done manually. The BIOS has to support manual settings to do that.

It's not going to blow up or anything but there are less expensive supported CPUs [the 950 and 960] that would be faster in the system than running the 955 under-clocked.
.
0
 
LVL 70

Expert Comment

by:garycase
ID: 24122863
On reflection, I've changed my mind => the 955 will almost certainly work (as I noted before); but it won't run at 2.60GHz ... it will run at 1.73GHz.

This is analogous to installing an 800MHz CPU in a system which only supports 400 & 533 MHz FSB speeds.   As long as it's the same family (e.g. Northwood) it will almost always work -- but will run at the 400MHz clock speed.

The 955 will almost certainly do exactly that -- run at the 533 FSB speed (= 1/2 of its rated 1066) speed ... so will have an effective clock of 1.73GHz.   There's no provision for scaling of the FSB, which my previous math (800/1066) had assumed.  PCBonez's comment r.e. "No divider/multiplier for the clock" is right if it was trying to run at 800MHz; but it will work just fine at a 533MHz FSB.

By the way, RAM timings and settings are based on the SPD from the RAM modules -- nothing to do with the installed CPU ... so you won't need to manually adjust the memory settings.   The BIOS will likely misidentify the CPU, since the 955 isn't supported; but otherwise it should work fine -- the voltage and muliplier settings will still be read correctly from the ID registers.

Agree there are clearly better choices if you were going to purchase a CPU for this ... but since you already have an unused 955, you may want to just try it.   The main issue is that it will run quite a bit slower than your current 830 [1.73GHz vs. 3.0GHz].
0
 
LVL 26

Expert Comment

by:PCBONEZ
ID: 24124982
> RAM timings and settings are based on the SPD from the RAM modules. <
~Bogus~

I can use the same RAM with CPU's of differing FSB and system will set RAM different for each CPU.
BIOS detects CPU and SPD data table, finds a match, and then sets the RAM there.
It will run at 400MHz because as system can't ID the CPU it will default RAM to the lowest setting.
 

0
How to improve team productivity

Quip adds documents, spreadsheets, and tasklists to your Slack experience
- Elevate ideas to Quip docs
- Share Quip docs in Slack
- Get notified of changes to your docs
- Available on iOS/Android/Desktop/Web
- Online/Offline

 
LVL 26

Expert Comment

by:PCBONEZ
ID: 24125042
That one is NOT going to run at 400 or 533 MHz.
It WILL be trying to run at 800 MHz.
The chipset only supports 1066 and 800 MHz.
http://www.intel.com/products/server/chipsets/e7230/e7230-overview.htm
0
 
LVL 17

Expert Comment

by:Nik
ID: 24125074
Agreed with PCBONEZ, as I stated above..
"Pentium 955 has a faster FSB, but that's limited by the MBO"
0
 
LVL 70

Expert Comment

by:garycase
ID: 24125075
Agree the chipset will restrict the available FSBs => which makes it very questionable exactly what would happen with the 955 installed.   Won't hurt anything to try it -- but it'd be very interesting to see what speed it runs at (assuming it will run).
0
 
LVL 17

Expert Comment

by:Nik
ID: 24125078
If it's the same socket, which in this case is, I don't see the reason why it shouldn't work, but with a limited FSB speed.
So, come on andrew_aj1, we're waiting for your call and reply :)
0
 
LVL 70

Expert Comment

by:garycase
ID: 24126591
"... If it's the same socket, which in this case is, I don't see the reason why it shouldn't work ..." ==> The same socket doesn't mean a CPU will work.   Most older P-IV boards, for example, won't accept Prescott CPU's; many have FSB limitations (400, 533, etc.);  and you need the appropriate BIOS support to properly recognize the CPU's feature set.   Even on boards that do support some of the newer CPU's, it's not uncommon to have to install an older CPU first so you can update the BIOS to include the support for the newer CPU (a frustrating "Catch 22" for those who don't have a few old CPUs laying around).

In most cases, a higher-FSB CPU will work in motherboards that don't support the FSB IF the board supports an FSB at the same base clock (e.g. an 800MHz CPU will work in a 400MHz FSB board;  a 1066MHz CPU will work in a 533MHz FSB board; etc.) -- but the CPU will be running at 1/2 of its rated speed (it will use the correct multiplier, but since the FSB is 1/2 of what's expected, it's running at 1/2 speed).    But even in these cases, if the BIOS doesn't recognize the feature set, the CPU may not perform as expected => for example, in this specific case, the goal is to use the hardware virtualization (VT) feature.   Since there ARE supported CPU's that have VT, the BIOS clearly recognizes and supports the VT feature -- so IF the 955 runs okay, it should work fine with VT.   But it's not clear exactly what speed the 955 will run at, since the chipset doesn't support a sub-multiple of the expected FSB.   Really just depends on the internals of the 955 -- it MAY simply run at the 800MHz FSB speed (in which case it will likely run at 2.6GHz, unless it also enumerates a different multiplier with the lower FSB speed -- in which case it may run faster);  or it may just not run at all.
0
 
LVL 26

Expert Comment

by:PCBONEZ
ID: 24126894
I agree, that's what I've been saying [or trying to] all along.
0
 
LVL 70

Expert Comment

by:garycase
ID: 24127174
andrew_aj1 ==>  I suppose the best answer to your fundamental question, "... Will this processor work in my server? ..." is MAYBE :-)

For the various reasons we've discussed, it may work fine at 2.60GHz;  may work at 1.73GHz; or may not work at all.   IF it runs, it should support VT okay (which is your primary goal).

Note that although the chipset specs only note support for 800MHz and 1066MHz; Dell indicates support for a 533MHz FSB in its specifications for the PowerEdge 830 ["... or a low-cost 533MHz FSB Celeron® option"], so there's a reasonable likelihood that the 955 will simply run at 533MHz (essentially running at 1.73GHz).

Bottom line is we don't know for sure => it depends on exactly how the 955 enumerates its features; what support the BIOS has; and whether or not the system will use a 533MHz FSB for a Pentium-D (rather than a Celeron).   But it won't hurt to try it => and if you do, be sure to post the results !! :-)


0
 
LVL 26

Expert Comment

by:PCBONEZ
ID: 24127437
>> Bottom line is we don't know for sure <<
Yes, that's exactly what I said here: -> 24119611  Author:PCBONEZ  Date:04/10/09 02:52 PM

There is a HUGE difference between experimenting with your own gear and with gear someone else paid for [and presumably depends on to pay the bills] just to satisfy your curiosity.

A Dell PowerEdge 830 is most likely business equipment and if so I don't recommend "playing with" the equipment.



0
 
LVL 24

Author Closing Comment

by:andrew_aj1
ID: 31568991
Thank you all for your help. It does not look like I will use this processor in this system as it will run slower than the current processor. I have a few other PowerEdge 830s deployed which do have Pentium 930 processors in them. I think I will just do a processor swap with one of them to achieve what I need.
0

Featured Post

6 Surprising Benefits of Threat Intelligence

All sorts of threat intelligence is available on the web. Intelligence you can learn from, and use to anticipate and prepare for future attacks.

Join & Write a Comment

Introduction: When a connection to the internet is established, there always exists a modem between the connected device and the ISP (Internet Service Provider). The Operating System (OS) on your PC controls the modem which communicates with the …
Learn about cloud computing and its benefits for small business owners.
This video discusses moving either the default database or any database to a new volume.
Polish reports in Access so they look terrific. Take yourself to another level. Equations, Back Color, Alternate Back Color. Write easy VBA Code. Tighten space to use less pages. Launch report from a menu, considering criteria only when it is filled…

747 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question

Need Help in Real-Time?

Connect with top rated Experts

11 Experts available now in Live!

Get 1:1 Help Now