Most everything I can find on the thermal master is that it is poor quality PSU that coolermaster rejected as being good enough to put their own label on it. Not one article was a positive review with most stating that it failed to deliver reliable power on its rails. The 400 was shown to max out around 280W and failed at the higher rated tests. Though it handled another PC okay you could place components at risk of failure. That choice is up to you though as whether to replace it.
If you have another PSU, try replacing it long enough to see if the errors stop. You also need to check to see if the card works in another system and it may be a driver error stopping your new system, or if it may be a ram error.