running command block checks repeatedly replacing blocks creates "server" lag

Can you show the commands you are using, and specify what type of clock it is?

{comparator fast clock}---{command: /fill ~2 ~ ~ ~28 ~ ~ stone } {command: /fill ~2 ~ ~1 ~28 ~ ~1 redstone_block 0 replace}

from "fast clock" strip
{repeater 3tick} {command: /testforblock -80 6 -477 minecraft:wool 0}{compartor}{command: /setblock -80 5 -478 minecraft:redstone_block 0 replace stone}
//above repeated 16 times for all wool colours, checking at -80 to -65x

{repeater 3tick}{command: /fill -65 5 -478 -80 5 -478 stone 0 replace redstone_block}
//replacing redstone_block from "behind" wool blocks of above commands in case wool removed
(was simplest way to check for NOT wool rather than making command above another 16 times with a inverted torch)

{repeater 3tick}{command: /testfor @p[-90,23,-267,4]}{compartor}{command: /time set 12900}
//also have 3 more of this command running to test for players in areas to teleport to other areas on map.

Hope that makes sense..

Another question, you have repeaters coming off @ three ticks, but those don't seem to be unpowering at all. How does that work?

ah but they are.. just not in that pic..
the compartor clock is just a little too fast for some of the commands used and it either doesn't register the redstone block update or burns out the torches.
If you want i can send you the world?

That would be great. I mirrored what you have in the picture to no avail, it wasn't doing what it looked like it should.

I am having the same problem but all the time. I think it cause the game cant keep up with 30-50 clocks that check at 20 times a second. I will upload the map as an attachment so you can test.

Its in 19a-26c

yes I have this same problem too and it happens when you have command blocks run consistently, this problem can be sped up if you have allot of 20 pulse per second command block clocks in minecraft running at the same time. with around 15 of these clocks running the game starts to encounter serious lag within 3-5 minutes. however when you break all the clocks the lag completely stops until you try to run any command or something, then the game lags for up to 4 seconds per command you enter. this usually fixes it self when you restart.

PS: When you close the game after it lags heavily, java happens to still run in the background of your computer, and for some reason it still uses a large amount of the power from the CPU, from 50% - 100%.

PPS: Still happens in 14w29b,14w30b,14w30c

Here is a perfect test world that should make this problem occur even faster
https://www.dropbox.com/sh/3im46t3ukqe0xr2/AABz1zcrRJ5O1nsP8tdDx-rla

I think this problem is related to java itself, because i'm failing to get the bug to show up again on both of my computers. This is happening sometime after both had a java update and now the bug doesn't appear in ether the newer or older versions of the snap shots, including the ones I claimed still showed the bug. I can't confirm if it was the java update that caused this bug to be fixed, because i get problems trying to rollback java. But from both of my computers, this bug is no more.

Is this still a concern in the current Minecraft version? If so, please update the affected versions in order to best aid Mojang ensuring bugs are still valid in the latest releases/pre-releases. If this has been done, we can reopen the issue.

Keep in mind that the "Resolved"-Status on this ticket just means "Answered", and that we are waiting for further information on whether this issue still exists or not. We will reopen it as soon as the requested information has been delivered.

Ticket resolved as incomplete, because no answer in a reasonable amount of time (1+ year), if it still happens, please update the ticket.