Epidemic workstation DRAM failure?

Not your normal post for this group, but as a small-time user I don't expect
a frank response from HP.

10 months ago we added 5 HP Compaq dc5100MT workstations to our LAN.

When the DRAM module failed in 1 unit after 8 months we got a replacement
from HP in 24 hours.
Now a 2nd unit has the same failure, and HP tell me delivery on replacement
module is 14 days - suspect demand may be high!

Obviously 2 fails is not enough to predict MTBF for this failure.
But 2 fails of a 4-chip module in 50 computer-months is not good.

Does anybody out there have good or bad experience of this model to share?

TIA
--
Newell White