Best CPU for a T400

[suddenthinkpadenthusiast]

Hello! I'm looking to upgrade the E8135 (T9550 equivalent) CPU in my T400. I'm eyeing a T9900 right now, but I wonder if Core 2 Quads would work. Would the cooling system be able to handle 45 watts, or should I stick with dual-core chips?

Also, I noticed that the T9900 and X9100 have the same clockspeed and cache, with the only difference being TDP. Which one should I choose?

[ajkula66]

Quad core won't work, no BIOS support in T400.

I'd say that a T9600 is a sweet spot for those systems, but if you want to spend $$ on T9900 feel free to do so. The difference will be marginal at best in terms of real life performance.

[kfzhu1229]

I have had both a T9600 and a T9900 (sweet deal, included on a Latitude E6400 that I paid less than the CPU itself is actually worth!), you can maybe get like 10% more performance in real world but you have to pay more than what the T400 itself is worth to get it, and it also runs 10% hotter because Intel's TDP ratings are quite shady.
A Q/QX/X series 45W Socket P CPU will basically slowly toast the VRM on those 14" machines to death even if the BIOS allows, full stop.

[unixed]

The T9900. It is E0-stepping and although pricey, is nowhere near what you'd pay for an E0-stepping X9100.
The advantage of the X9100 is that it has an unlocked multiplier, so you can overclock it. However then you'd have to dissipate the extra heat, no mean feat.

[kfzhu1229]

The T9900. It is E0-stepping and although pricey, is nowhere near what you'd pay for an E0-stepping X9100.

I think you meant compared to the X9000... All boards compatible with X9100 will work with a X9000 but not necessarily the other way around. And since without BIOS mods you cannot use a X9100 in these regular business class machines and that most of them also have cut down amounts of VRM's compared to the previous Merom-Penryn generation of boards, the X9100 is cheaper than you think.
Over here we have to pay $20 more for the T9900 than a X9100 and that is assuming that the first listings I see are not fake CPU's.
The X9000 over here (C$125) costs more than double the amounts of money compared to a X9100 (C$50) and luckily pre-corona I bought the X9000 at the price of a current X9100

[suddenthinkpadenthusiast]

Thanks for your help with choosing a CPU! I auction-sniped myself a T9900, and it should be arriving soon. I got a pretty good deal for it (I paid around as much as an X9100 goes for on eBay). I'll make sure to keep you all posted.

Even though I'm only using a 35W CPU, I added thermal pads from the VRMs to the CPU heatsink to dissipate more heat because I'm considering overclocking the T9900. Even though it has a locked multiplier, I should be able to overclock the CPU with Throttlestop, right?

My E8135 with an identical stated TDP runs at 60 C during a Prime95 stress test with the stock fan curve, so I think the system has enough thermal headroom for a 44W CPU or some overclocking, given that I gave the VRMs a much better cooling solution?

Also, I understand that steppings can alter the properties of a CPU (like the G0 Q6600). However, I don't know what exactly the E0 Penryn stepping does. Is it a simple efficiency improvement?

[kfzhu1229]

Even though I'm only using a 35W CPU, I added thermal pads from the VRMs to the CPU heatsink to dissipate more heat because I'm considering overclocking the T9900. Even though it has a locked multiplier, I should be able to overclock the CPU with Throttlestop, right?

My E8135 with an identical stated TDP runs at 60 C during a Prime95 stress test with the stock fan curve, so I think the system has enough thermal headroom for a 44W CPU or some overclocking, given that I gave the VRMs a much better cooling solution?

Nope you cannot use throttlestop to raise the speed to anything above the stock max speeds, nor can you overvolt. Those are reserved for only unlocked CPU's. You can however undervolt. I believe there are mods that allow you to get a slight bit of boost kinda like turbo boost unlock but in the end we are still talking about performance that's a country mile away from something like an i7-3630QM that you can get at almost the same price as a T9900.
And well cooling is only one side of the puzzle to overclocking. Your motherboard simply cannot handle it as it's beyond the official maximum for the MOSFETs. You are asking the motherboard to deliver too much power to the CPU at that point. Cooling the VRM's help but well it's just like how you won't be using a liquid nitrogen-cooled overclocked Core i9 on a daily basis.
The Centrino 2 laptops have much lower powered P series processors to play around with, while previous generation only had 35W CPU's so their MOSFETs are beefier.
And well going from T9550 to T9900 is a questionable of an upgrade in terms of value but not pathological. I bought the X9000 because I came from a T7250, which is like half the performance of the X9000, and that Dell is nice enough to provide official BIOS support for X9000 so it was totally painless.

[unixed]

Every X9100 you've found for your quoted price range has an S-Spec of SLB48 indicating that the core stepping is C0. That is a different animal. The later core stepping is more efficient and has an S-Spec of SLGE7. Try and find that then look at the price.

[kfzhu1229]

Every X9100 you've found for your quoted price range has an S-Spec of SLB48 indicating that the core stepping is C0. That is a different animal. The later core stepping is more efficient and has an S-Spec of SLGE7. Try and find that then look at the price.

https://www.ebay.ca/itm/Intel-Core-2-Ex ... SwH21fiN42
Though these stepping might not matter anyways as these might just be fake CPU's either way.
And none of them would work with a T400 anyway (not without risking to burn your motherboard). You can't expect it to work flawlessly when not even the W500 or the 14" workstation Precision M2400 has support for the X9100

[unixed]

You notice that the photo is of a C0-stepping X9100? Try again.
It is the OP who is interested in comparing the T9900 and X9100, wanting the best, so I obliged.

I could run the X9100 in a T400 and have in a T61, but I prefer the T9900 and can run both cores at 3.2GHz if I want in a R500.
There are enough threads showing we aren't limited by whether the manufacturer supports a certain CPU or not, particularly in the T60/1 forum.

[suddenthinkpadenthusiast]

Thanks everyone for the help! My T9900 should be arriving tomorrow; I'll let you know how it goes.

Also, I know that one variant came with the HD 3470 GPU. I have another T400 somewhere that has that dGPU, but I'm wondering if it'll turn into any real-world benefit. I plan to use the T400 for regular office work and perhaps some emulation via Ishiiruka Dolphin (which I believe uses CPU emulation for the Wii's GPU). However, I noticed that that Thinkpad got significantly hotter than the non-dGPU version even at idle. Are switchable graphics drivers able to completely turn off the GPU when it's not being used? Will it translate into any real-world benefit via hardware GPU acceleration?

[TPFanatic]

You can disable dGPU inside BIOS (make sure to turn off OS Detection as well or it auto-reenables it if you're booting Win Vista or newer). That'll stop it.

If the dGPU is enabled, it will run hot if the drivers are not installed.

[suddenthinkpadenthusiast]

You can disable dGPU inside BIOS (make sure to turn off OS Detection as well or it auto-reenables it if you're booting Win Vista or newer). That'll stop it.

If the dGPU is enabled, it will run hot if the drivers are not installed.

I installed the appropriate driver as provided by Lenovo's EOL portal, but it still runs quite hot. Can the GPU be dynamically switched on and off by software as needed, or is the Mobility HD 3470 too old for that?

[TPFanatic]

It can be switched off in the OS manually with Power Manager, yes it is too old for dynamic control.

It can also be running hot if the thermal paste is dried up. Although I recall my T500, even when fully optimized, still got plenty hot underneath. Might just be a perk of the design.

[suddenthinkpadenthusiast]

It can be switched off in the OS manually with Power Manager, yes it is too old for dynamic control.

It can also be running hot if the thermal paste is dried up. Although I recall my T500, even when fully optimized, still got plenty hot underneath. Might just be a perk of the design.

Ah I see. I'd prefer battery life over GPU performance (especially since the 3470 is almost nothing in today's standards), so I'll stick with the iGPU version of the motherboard. Also, what exactly does Lenovo Power Manager do? Should I install it, or is it unnecessary?

[TPFanatic]

Power Manager is a very useful tool for Windows XP, Vista, and 7, providing a more user friendly GUI than Windows Power Plans. You need Power Manager to switch between GPUs while in the OS (compatible with Vista and 7 only). It isn't supported and doesn't work correctly in 8 and 10. Power Manager also displays information from the battery and gives you a GUI for setting battery charge thresholds, one of the greatest ThinkPad features for increasing battery lifespan. I recommend it if it's compatible with your OS.

[suddenthinkpadenthusiast]

Thanks to everyone who helped me with my T400! My T9900 came today and it's up and running just fine. I really appreciate all the help!

[kfzhu1229]

Thanks to everyone who helped me with my T400! My T9900 came today and it's up and running just fine. I really appreciate all the help!

Hmm also I am wondering if you would have your old CPU for sale. I have an incoming Dell Inspiron 1440 that's currently rocking a Pentium dual core and it would be nice if I can get your CPU working up there instead. I am trying to fish out the screen out of it because it seems to have one of those great looking HD+ panels

[suddenthinkpadenthusiast]

Thanks to everyone who helped me with my T400! My T9900 came today and it's up and running just fine. I really appreciate all the help!

Hmm also I am wondering if you would have your old CPU for sale. I have an incoming Dell Inspiron 1440 that's currently rocking a Pentium dual core and it would be nice if I can get your CPU working up there instead. I am trying to fish out the screen out of it because it seems to have one of those great looking HD+ panels

Sure, I'd be happy to discuss this with you! I have several CPUs that should be compatible with your system, according to the CPU compatibility list for the GM45 Express chipset. I think you'd obviously want the E8135, but I also have a P8600 and T3400.

[kfzhu1229]

Hmm also I am wondering if you would have your old CPU for sale. I have an incoming Dell Inspiron 1440 that's currently rocking a Pentium dual core and it would be nice if I can get your CPU working up there instead. I am trying to fish out the screen out of it because it seems to have one of those great looking HD+ panels

Sure, I'd be happy to discuss this with you! I have several CPUs that should be compatible with your system, according to the CPU compatibility list for the GM45 Express chipset. I think you'd obviously want the E8135, but I also have a P8600 and T3400.

Actually I will have both the E8135 and P8600. Can you DM to me about the details and how much you want from them?
I have read that the Inspiron 1440 only came with lower end T series processors (T6xxx or lower) and P series processors so I am afraid if Dell skimmed on VRM on that thing so much that it can't handle a T9xxx processor.
Thanks

[Ignorant]

wher is this LEnovo EOL portal?.
I want to download W7 64 bit display driver for T400 integrated graphhics

[axur-delmeria]

https://download.lenovo.com/eol/

[Ignorant]

Use the w7 drivers in compatibility mode.They work great even with a 1400X 900 tubelight LCD.