RAM woes..............Help guyz

[techmax]

i have got two ram modules

1.Original Simmtronics 256MB (333 mhz)
2.Irvine (not familiar with this company) 256MB (400 mhz )

Motherboard:
ECS 845GV-M3 supporting max of 333 mhz modules

http://www.ecs.com.tw/ECSWeb/Products/ProductsDetail.aspx?DetailID=465

Problem:

i was watching some video files via media player classic and tried to decrease

the speed of the video ,the system restarted abrubtly, and on startup yahoo

messenger gave an error stating that a memory location cannot be read

i checked both my moduules(seperately) via memtest86 v1.60 and no errors

were encountered but when i tested both the modules together many errors

were encountered in TEST 8 ( modulos of 20 test) i again tested each mod

seperately again no probs then why there are errors when putting both

together

[wizrulz]

were u using those modules be4 also or newly put to use???

[techmax]

i was using both the modules together(for abt 2 months) while the problem occured