100% Defective or just Poor Quality?

I have a 1gb corsair xms ddr2 800 (5-5-5-12) and I've been running memtest on it. I have to underclock my fsb to 266 (memory speed at 266, 1:1) in order to have no errors on test 5. The timings are manually set and voltage is at 2.00 (stock is 1.9) If change the fsb speed to 400 and memory to 400, it will give me errors on test 5, always between 2 addresses.

So my question is ...is the memory completely defective or just poor quality? Is there any other way I can eliminate those errors without RMAing or underclocking/increase timings?

Edit: Only some passes show the error, but when it does, it shows like errors from previous passes (its 2 errors per pass, but sometimes pass 0 and 1 don't show anything and pass 2 shows 4 errors).

If there's any errors running at their rated speeds and timings, then they are defective, so either contact the vendor from which you purchased them to setup an RMA, or contact Corsair directly for an RMA.

Hmm it seems that when I use the SPD enabled it won't even post (its default at 5-6-6-15-6-42-10-10-10) and

There are errors from memtest when i use the default settings for the:
write recovery,
trfc,
trrd,
rank read to write,
read to precharge,
write to precharge,
(all from SPD)

However, by changeing it to 5-5-5-12-6-42-3-11-5-14 manually, it passes memtest with 0 errors. .. kinda confusing for me. Anyone have a guide that explains the write recovery, trfc,trrd,rank read to write, read to precharge and write to precharge all means?

And should increasing/lossening the timings without increasing the fsb generate more errors?

Edit:

The results I'm getting from memtest are.. really weird. I've been running test 5 only, but i get 4 errors on pass3, 4 errors on pass 4, 2 errors on pass 5, no errors on 6,7 and 8, 2 errors on pass 9. what kind of anomaly is this? =??

if you have manually set all of the timings/voltages and it's still even giving ONE error, then they are bad. Sorry for the news...but it's RMA time

Thanks for replies, the ram wasn't faulty. just the spd was way off on the timings. I readjusted the timings to be what its rated and fairly loose (5-5-5-12//-6-35-2-10-5-12) at 443 and 2.1v. 3 hours and counting on memtest

I think its faulty if you have to manually set the timings to lower then what they should be doing to not get any errors, but if you can live with the lower timings...

lower is faster the 4 main ones are set at what their rated. its the 6 other ones that i had to play around with. Im getting about a 80 mhz overclock out of it so im satisfied.