Thinkstation P3 Tiny Gen 2 Thermal Issues

Posting here in case anyone has experience with similar thermal issues on the Thinkstation P3 Tiny series. Hopefully Lenovo Support can chime in!

I bought an unused open-box Thinkstation P3 Tiny Gen 2, with a Core Ultra 5 235 and a single 16GB DDR5 SODIMM. I upgraded it with 32GB DDR5, installed a new boot drive (2TB 980 Pro) replaced the CPU with a Core Ultra 7 265T (35W) and installed a small form factor GPU (4070M frankencard).

Immediately upon attempting to game with the machine, I noticed severe stuttering after just 5-10min of gameplay. Despite being entirely GPU-limited, with CPU utilization at only ~25%, the CPU was hitting 93°C and thermal throttling, according to CoreTemp. (GPU was at ~50C, for reference)

Before anything else, I did a repaste and reseated the cooler, assuming I had messed it up somehow. But that didn't change the behavior at all-- in fact, it was idling at ~75C on the desktop.

I installed FanControl, but quickly learned that Thinkstation Tinies don't expose fan control to the OS. It's all handled by the BIOS.

The BIOS has three fan speed options:

• Balanced
• Performance
• Full Speed

Both Balanced and Performance result in the CPU reaching 90-95C within minutes of any kind of gaming, causing extreme thermal throttling and stutter in the OS and games. Full Speed sounds like a jet engine but keeps temps reasonable (idle at ~40, ~75 max).

Other things I tried:

• Repaste and reseating heatsink, as mentioned before
• Swapping back in original boot drive (maybe it shipped with some driver or service to handle thermals? Nope)
• Swapped back in original Core 5 235 CPU (no change)

I've never had this issue on any desktop PC I've built from scratch, nor on any laptop. They have all defaulted to reasonable fan curves that prevent thermal throttling, and/or expose fan control to the end user in the OS.

Basically, the Full Speed option keeps temps under control, but the Balanced and Performance fan curves never actually ramp the fan up that high, and exhibit extreme thermal throttling as a result, which makes gaming impossible.

This is just baffling, and it's still doing it with the 35W 265T I swapped in, which is a processor with half the TDP of the original CPU it shipped with.

Lenovo Support, is this intended behavior? I'm not seeing anyone else complain about this so it's unclear if it's normal. If it's expected behavior, please release a BIOS update that provides a throttle-free fan curve option. A PC that thermal throttles this badly just to avoid fan noise is quite literally unusable for SFF gamint. My only remaining option is to cut the CPU fan wires and install some kind of separate fan controller, which is extremely unreasonable for a $1000 machine.