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We upgraded our COMSOL workstation CPU from an AMD Ryzen Threadripper PRO 7985WX to an AMD Ryzen Threadripper PRO 9985WX. Both systems have 256 GB of RAM.

On paper, the 9985WX is a newer and higher-tier CPU, but in COMSOL we’re seeing the opposite: performance feels clearly worse.

What we’re experiencing in COMSOL

• Geometry operations feel noticeably slower (changing geometry, rebuilding, etc. takes longer than before).

• During a solve, the UI and model interaction stutters / becomes laggy much more than it did on the 7985WX.

• Overall, the 9985WX system feels less responsive in COMSOL than the 7985WX system. CPU core utilization behavior looks different

We monitored CPU core activity:

• On the 7985WX, COMSOL tends to use the cores in a more uniform / evenly distributed way.

• On the 9985WX, COMSOL appears to leave several cores almost idle.

To rule out a hardware issue: • We applied external CPU stress/load tests and confirmed that all cores do run and boost properly under load.

• We also checked the rest of the hardware and did not find any obvious faults.

Thread/core settings tested (no improvement)

We tried changing COMSOL’s Number of cores setting:

• Using the default value.

• Manually setting values across a wide range: 48 up to 128.

None of these settings resolved the issue.

Memory behavior

Even though both machines have 256 GB RAM, we also observed that the 9985WX system uses noticeably more memory for the same work compared to the 7985WX system.

We request a solution or recommended configuration to restore expected COMSOL performance on Threadripper PRO 9985WX.