Try using Windows 8.1.

There's an issue, IIRC, in which Windows 7 can't detect more than 4 cards (8 cores).

Since you haven't specified the GPUs you're using, I assume its a dual core ones, so that might be the problem.

There are two forks of CDC. That's why there are different starting heights.

228898+ is the old chain which is stuck (PoS only, no PoW). Only older clients v1.0 (/Satoshi:0.7.2/) will be on this chain, but newer clients can use it to partially sync.

282957+ is the newer chain, which all clients can use: v1.0 (original), v1.1, v1.2.

CDC is hard to mine because PoS fights with PoW; a single PoS block can orphan the end of the chain that contains PoW blocks. Mostly this is just one or two blocks, but sometimes it can be 10+ blocks that are orphaned and replaced with the PoS block. CDC is not the only coin which is PoS heavy.

What about Greecoin on coinmarketcap?  

And one day, CDC quickly raised!

Thanks a lot, that's what I was looking for I repeat, the 2nd PSU will  be powering 3 cards along with their risers separately from everything else, although all 6 GPUs will be connected to the same motherboard. There shouldn't be a risk of mixing electricity or anything of the sort

I was the one that revived it. Not sure you could call me a maintainer though. May look at compiling a newer client with a couple of bugfixes and checkpoints.