G4 silver locks up when streaming media in safari and Firefox.

Question

G4 Silver, OWC Mercury1.4,1g Ram, OEM Video Card 2HD’s 10.3.9 and 10.4.11
This machine locks up when playing streaming media in Safari. This is a long standing problem on this machine. The symptoms occur a few minutes in to the Daily Show or BBC News or whichever media site I’m watching, it freezes, sometimes there is a sound loop that gets stuck and will play over and over until I shut down the machine. It always requires a hard boot to restart. It often requires several boot attempts to get it to reboot. The machine will chime but the screen stays black. On really bad days I will get kernel panic messages on the reboot but most often just booting over and over 2 or 3 times brings everything back up. The longest I’ve had to spend getting a reboot is about 50 mins. of repeated boot attempts.
I have done several verify and repair disk, and permissions repairs. I’ve run Techtool and it reports no errors on processor, memory, Video, HD or functions. I tried swapping out Video cards. This freeze happens using either HD one is loaded with 10.3.9 and the other 10.4.11 both OS’s will crash under the same circumstances. I have unplugged all peripherals. I’ve put in 2 new sticks of OWC Ram. All software is currently upgraded to latest versions. A DVD will play all the way through without crashing the machine. I’ve tried running the Mac Hardware Diagnostic Disc and get a mother board error but that is to be expected with a 3rd party OWC processor. I don't have the original processor I believe this to be a false error. The only thing that crashes this machine is playing downloaded/streaming internet media. I've got crash logs but have no idea what to look for. Any of you want to weigh in on this one.
I have 2 silvers a Blue G4 and a MB PRO. I've had an SE, 7500, 8500, G3 Tower. I've never had something I can't solve. This one has been a 2 year problem. I thought adding the 2nd HD and a fresh install of Tiger would cure it. Thought wrong again.

Answer 1

Remember/Memtest crashed the machine within 4 minutes. I took all of the ram out and tested them one stick at a time. they all tested good. Strange I noticed that *all OWC Ram reprots to be PC100-322S, rather than 133.* This is across the board in both G4 Silvers and a Blue Digital. I then ran Chess, it Crashed the first 6 times. The procesor hits around 118-120 degrees. I have an infrared heat gun and can measure the cooling fins on top of the OWC Mercury Extreme Gold. Game #7played all the way through, # 8 crashed and #9 played but was only about a 10 move game. I called OWC and was on hold for about 30 minutes with tech support and then got shuttled over to service for an RMA. I got cut off from service and it was then too late to call back. Service wanted some numbers off the Processor. The service guy insisted I'd find numbers on the side of the processor, but I had to power down and take it off the MB to get numbers. They are all on the bottom. I'll call OWC back on Monday and try again. I still have the original instalation instruction sheet. I found it while looking for the processor box in my old too good to get rid of containers.
Thanks for steering me towrd Chess. I found the FAC at OWC while waitin on hold for those 30 minutes. I'd liked to have know a year ago when I called them about the possibility of having a flaky processor.