Deskpro EX (P866) - Processor change (413 Views)
Occasional Contributor
Posts: 4
Registered: ‎03-25-2008
Message 1 of 5 (413 Views)

Deskpro EX (P866) - Processor change

I got "new" processor for a bargain price and decided to try it on my Compaq Deskpro EX which is currently running with original PIII 866MHz processor.
The "new" processor is Intel Celeron (SL5XS) 1.2GHz.

However; when I mount it in and boot up my PC, nothing happens. No beeps, no text on a screen - nothing... HDD- and Power-leds are working tho and DVD-drives light flashes couple of times but then it's all silent.

That's 100% sure that the Celeron processor is not damaged. That's guaranteed.
Is it just that my motherboard doesn't support that model of Celeron or what's the matter?

Here's more information of my PC:

SiSoftware Sandra

Model : Intel(R) Pentium(R) III
Speed : 864MHz
Performance Rating : PR1037 (estimated)
Cores per Processor : 1 Unit(s)
Threads per Core : 1 Unit(s)
Internal Data Cache : 16kB Synchronous, Write-Thru, 4-way set, 32 byte line size
L2 On-board Cache : 256kB ECC Synchronous, ATC, 8-way set, 32 byte line size

Bus(es) : X-Bus AGP PCI IMB USB i2c/SMBus
MP Support : 1 Processor(s)
System BIOS : Compaq 686P0 v2.04
System : Compaq Deskpro
Mainboard : Compaq 06C4h
Total Memory : 512MB SDRAM

Chipset 1
Model : Intel Corporation 82815/EP/P Solano Host-Hub Interface Bridge (GMCH/MCH A2-step)
Front Side Bus Speed : 1x 133MHz (133MHz data rate)
Total Memory : 512MB SDRAM
Memory Bus Speed : 1x 133MHz (133MHz data rate)

Video System
Monitor/Panel : HP D8905
Adapter : RADEON 9200 SERIES - Secondary
Adapter : RADEON 9200 SERIES

Physical Storage Devices
Removable Drive : Floppy Drive
Hard Disk : Maxtor 6Y080L0 (76GB)
Hard Disk : WDC WD200EB-11BHF0 (19GB)
CD-ROM/DVD : HL-DT-ST DVDRAM GSA-4081B (CD 63X Rd, 16X Wr) (DVD 8X Rd, 2X Wr)
CD-ROM/DVD : Plextor PX-TV402U SCSI CdRom Device (CD 32X Rd) (DVD 4X Rd)

Serial/Parallel Port(s) : 2 COM / 1 LPT
USB Controller/Hub : Intel(r) 82801AA USB Universal Host Controller
USB Controller/Hub : USB Root Hub
Keyboard : Standardi 101/102-näppäiminen tai Microsoft Natural PS/2 Keyboard
Mouse : Microsoft PS/2 Port Mouse (IntelliPoint)
Mouse : Microsoft USB Wireless Mouse (IntelliPoint)
Human Interface : HID-compliant consumer control device
Human Interface : USB Human Interface Device

MultiMedia Device(s)
Device : Intel(r) 82801AA AC'97 Audio Controller

Power Management
AC Line Status : On-Line

Operating System(s)
Windows System : Microsoft Windows XP/2002 Professional (Win32 x86) 5.01.2600 (Service Pack 2)

Network Services
Adapter : SMC EZ Card 10/100 PCI (SMC1211TX)
Honored Contributor
Posts: 4,061
Registered: ‎01-20-2003
Message 2 of 5 (413 Views)

Re: Deskpro EX (P866) - Processor change


The Deskpro EX comes with two different chipsets the 810e and the 815. The 810e motherboards only support up to 866 MHz processors.

You have the 815 chipset according to your information. The 815 chipset supports up to 1.7 GHz Pentium III so I would expect that it would support a 1.2 GHz Celeron processor also. However none of the Deskpro EX models came with Celeron processors over 700 MHz.

Hope this helps.

John K.
Honored Contributor
Posts: 9,770
Registered: ‎10-20-2002
Message 3 of 5 (413 Views)

Re: Deskpro EX (P866) - Processor change

The problems with this proposed upgrade are:

1. The Celeron 1.2 is designed for FC-PGA2 and the Compaq system board has an FC-PGA socket. The processor is not compatible with the socket.

2. The chipset is running the FSB at 133 MHz. The Celeron is designed for a 100 MHz FSB.
Occasional Contributor
Posts: 4
Registered: ‎03-25-2008
Message 4 of 5 (413 Views)

Re: Deskpro EX (P866) - Processor change

Ok. Thanks for the information guys. :)

Unfortunately Steven is right as far as I found more information by myself. :/

But... Fortunately that doesn't hurt much financially because the processor was very cheap. Just thought to give it a try and ask for information.

If I'm about try a processor change again in future, could you give me information what exact processors are supported by my motherboard/socket/BIOS? Thanks in advance.
Honored Contributor
Posts: 9,770
Registered: ‎10-20-2002
Message 5 of 5 (413 Views)

Re: Deskpro EX (P866) - Processor change

The processors that are compatible with a socket that uses a PIII/866MHz would be the other Coppermine PIII processors for 133MHz FSB. These go up to 1.13GHz, but the 1.13 and the 1.0 were reportedly prone to heat problems. There are adapters available for FC-PGA2 processors, which would include for example the PIII/1.4GHz. See an adapter here:

The BIOS apparently recognizes up to 1.2GHz with the latest download:

However, many Compaq computers will work fine with processors not correctly recognized by the BIOS. You just install a program that skips the error message when booting up. It's here:
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