Dell PC showing orange LED after changing the Processor

[gunturandy1]

Hello, this is the first time i write on here, sorry my English is bad.

I have CPU dell optiplex 745 mini tower. It has Pentium D 3.4 GHz
And i change it with core 2 duo e8400 3.00 GHz. My PSU 305 Watt, standard. And after i connect the power it suddenly turn on and show orange LED. And did not start only fan is on

 

[Wolfshadw]

Looking at the Optiplex 745 Tech Specs, I don't see the Core2Duo as an option. Even though they're the same socket, it doesn't mean it's compatible.

-Wolf sends

 

[william p]

The E8400 is too new for that machine. It can't run 45nm CPUs, only 65nm 266/1066 fsb versions.
Get the latest BIOS from Dell which will install itself in Windows easily. Then pick a CPU from what you see running here.
http://www.userbenchmark.com/System/Dell-OptiPlex-745/3949
It can run 130W 65nm Core 2 Extremes. QX6800 SLACP 2.93GHzis the best, SL9UK is ok if you won't be overclocking X6800 is the 2.93GHz unlocked 2 Core. QX6700 2.66 is unlocked but at standard speed the Q6700 is better. E6700 is the 2.66 Ghz standard 2 Core.
No reason to run the Q6600 in this machine

 

[gunturandy1]

Sorry, my bad. Owh, nice information, thanks william p. So, core 2 quad could work in 745? Or, every cpus that 65nm?

 

[william p]

Ther was a QX6850 65nm that was 333/1333 fsb 9x333=3Ghz. So not aALL of them.
I've run the QX6800 @ 3.45Ghz using Throttlestop 6.00 software. But it just about equals a Q9650 in a 1333 capable Optiplex 755,760,780.
The 745 actually supports Pentium4 and PentiumD CPUs, so getting a Core2Quad to run is actually pretty good.

 

[gunturandy1]

So, in your opinion what is the best choice for dell 745, n do i need to do something to my cpu?

 

[william p]

For an overclock the QX6800 SLACP, for fastest base clock any QX6800, for a cheap solution the Q6700. You need an older CPU.