can't detect the memory

hi!! recently i bought a mermory Twinmos DDR 128mb (a friend sold it to me at very cheap price ) , i already have a Kingmax 256mb (2 x 128mb).. but now the problem is that everytime i put them all together the system only can detect 128mm & if i mix them up in those 3 ram slots it can dtect 256mb but there's no way it detected 384mb.. is there something wrong with the RAM slots?? or mixing up different brand of RAMs may effect the system?? i tried all of my DDR Rams one bye one & they are all working well

1st: Memory defective. Have you tried Memtest86 to see if you have errors?

2nd: what's the comp specs?

What speed DDR?
Also, very diffent latencies will cause incompatabilities.

AMD or Intel -based motherboard?

i havent tried that Memory test.. my PC is AMD based, i have an ASUS A7S333 motherboard..

like i was talking about in the other form,it sound like it is a problem because of cheep ram,i hade this VERY problem,..i hade a couple GB's in and i got 2 more GB's and i went cheep and every time it would mess up the other 2 because i went cheep...if they are not bad and they are the same speed (DDR333 or so) then it is because of the cheep memory chips used on the cards.....

P.S. i have a 512MB Stick of Simple Tech(PC3200 / DDR400) for sale because it wont met my other computers ram sticks work..nothing wrong with it,just need to be used with other simple tech or ram that FOR SURE well work with this brand....PM,me if u want to know more...

but that is what it sounds like to me.....

Some times varying latencies wont work. Like the original ram may be a latency of like 2 or 3, and the cheap stuff would be like 6. Kinda like plugging a 4ohm sub to 2ohms and cranking it up. Crap aint gonna run right.

Try one stick a time. If you see the computer not booting, then the memory is crap

all the sticks are working fine alone.. but everytime i put 3 (128mb) of them the system only reads 256mb..

Some times memory of vastly varying latencies will not work together.

Do you have onboard video?

no i dont have onboard video..

Then my professional opinion of such would be that you simply have incompatable memory. Mixing the problematic chip with a single chip of the other memory yeild the same problem?

yes, it seams that Kingmax & Twinmos are incompatible i have'nt check yet what their chipset is..

are you sure you friend likes you?

I think I just wet my pants.