MAX and two 128MB DIMMs, problems

[Barry]

My system has same problem,but my card is G400 sh 32M(overclocked to MAX),My screen hangs when I inserted 3 Kingmax PC-133 128M,the screen freezes or shows a lot of lines(like G400 overclocked too high)randomly.I am sure that memory ,CPU,and G400 works fine when using only 256M.
My system configuration:
WINDOWS 98 SE
POWERDESK 5.52
C300A OC 525(117*4.5)
MS6163PRO
VIEWSONIC PT813
AHA-2940UW
SB-LIVE VALUE
SEAGATE BARRACUDA 13.6
IBM DDRS-4.5
PLEXTOR 820
PLEXTOR ULTRAPLEX 40 MAX
ASUS 8X DVD
ROLAND SCC-1
SEVENTEAM 400W POWER