sudden spurts of "time-too-old" rejections

[Merrick]

So I've been pool mining ltc for a while with multiple pools and was not seeing more than maybe 1-3% rejections, mostly when a new block hit...

Last couple of days, I can start a cgminer session on either of my rigs (one at 2.7.5, one at 2.6.1) and it chugs along fine for a minute or two... then it starts periodically flailing about with a ton of rejects for "time-too-old" and does that every couple minutes before recovering, resulting in about 30-50% reject rate... (on any pool)

Nothing has changed with my network connection or bandwidth (20mbit down) as far as I can tell. No updates or changes to the mining sofrware, drivers, sdk, etc...

These things are hasing at 100mh/s per card minimum, so I can't see how they'd be taking too long to submit shares...

So, not limited to pool, not limited to cgminer version, not limited to machine, and bandwidth seems to check out. Any suggestions as to why I'm rejecting a ton more?

I would appreciate any constructive input. Thank you.
Is my ISP just crap?

-M

[1714895454]

1714895454

[Merrick]

as an added note, I don't have any issues when solo mining ltc or ppc.
I also have no issues pool mining btc...

Why doest thou hate me, ltc?

[wndrbr3d]

I've been running into this same issues with both my 5870 and 6870 while mining for litecoins using CGMiner (2.7.6) on my private pool. I've checked my instance of pushpool and it's not under any heavy load and I've restarted it several times to no avail. What happens is it'll mine ~350 shares using my 6870, then it'll begin returning THOUSANDS of hardware errors before CGMiner just crashes.

I find using CGMiner 2.6.4 results in fewer errors and it won't crash out, just returns ~10-15% stale.

Basically I start getting time-too-old errors and then CGMiner just crashes.

Anyone have any ideas?

[tacotime]

This has been happening to me since the dawn on GPU mining LTC on pools.  Not sure what causes it.

[wndrbr3d]

Just posted a reply about it to the CGMiner thread. Let's see if it gets flamed or anyone actually helps

https://bitcointalk.org/index.php?topic=28402.msg1231316#msg1231316

[rahlquist]

Getting close to 50% reject rate with this error now. Guess its time to give up on LTC for the time being.

[wndrbr3d]

Getting close to 50% reject rate with this error now. Guess its time to give up on LTC for the time being.

I found 2.6.4 to be the magic number for me. Give that version a try.