I had this happen to me, I don't remember if the stick was single or double sided, but it worked well on a different motherboard. So I'd test this stick on other motherboards. I think it will probably work.

You could also check the individual memory chips, look for the datasheet and find out what's their capacity.

VIA 133A Pro chipset

Are you sure?

Via had the VT82C693A ApolloPro133 and the VT82C694X ApolloPro133A. Given the behaviour you are observing, I strongly suspect it's a VT82C693A ApolloPro133, as it supports max 128Mb per chip, where its successor supports 256Mb per chip. If your DIMM has 256Mb chips, this is exactly what you would expect to see.

As for how to determine chip density: simple math: count the number of chips on the DIMM. Divide capacity (256MB) by that number (either 8 or 16), then convert to bits by multiplying by 8. In this case even simpler: if it has 8 chips, they are 256Mb chips; if 16 chips, then 128Mb chips.

If that's not it, it might be relevant to post exactly which Gigabyte board this is. An So370 Gigabyte board with Via chipset would have a name like "GA-6Vxx7" printed somewhere on the motherboard.

Its the GA-6VXC7-4X-P with the 694x chipset. According to the manual it supports up to 512 per ram.

I have already a 256mb single sided ram with 8 chips in and it works fine.

The ram i bought is a kvr133x64c3/256 double sided with total 16 chips and this shows only 128 mb.

The interesting thing is i have also 2 x 128mb inside both doublesided with 16 chipsand theywork also fine.

The idea is to replace the 2 x 128 with 1 x 256.

In total i have atm 512

>kvr133x64c3/256 double sided with total 16 chips

single sided with 8 32MX8 NT5SV32M8BS-75B chips
post a picture of yours

EDIT: found another one with 16x 16Mx8 TC59SM708FT-75
and another one with 8x 32MX8 HY57V5682
Kingston dgaf

second thing you could do, after posting a picture, is find a program able to read SPD (cpu-z, sisofsandra etc) and check what the ram reports back

Here is the picture from ebay

I bought another now, this time one sided, hopefully i have more luck with that. Since it was only 5 euro ill give it another try

Just try a different stick. Some internal silicon configurations work when others dont