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Level 1

12 points

10.5.6 causing terribly slow Internet access

I have of course been searching on this for a while now, a few weeks, but every result is usually some conclusion about DNS issues, which I find tough to believe is the cause for two reason.

1) I have wiped clean my iMac and reinstalled everything fresh, no restored data and everything was as quick as it had ever been up to 10.5.5, installing 10.5.6 either by 5.5>5.6 patch or the entire combo update has caused many internet enabled applications to take a painfully long time to load information.

2) One of my friends supporting a university Mac OS (etc) network has said that this same issue has been reported on about 190 of his machines.

My DNS is cached locally on the router and is used by my PS3, 360, iPod Touch, PSP, DS, Windows XP machine & iBook (10.3.x), the only two devices with any problems at all are the two 2008/iMacs and only when they run 10.5.6.

So, getting that out of the way has anyone got any news about this? Has anyone found a solution that does not lay blame entirely on the DNS server?

The two prime examples would probably best be Safari 3 had gone from loading pages with ease to the connecting phase for several seconds to upwards of a minute before a page even starts to load, on other occasions loading about 70% of a page and the last 30 taking a good while to complete. This is also true of Safari 4 beta.

I use dashboard a lot, I use the weather widgets every morning before I go to work and under 10.5.5 or below the access time was from immediate to 2 seconds maximum. I am now waiting 20 seconds or double every time I load DB up to check.

There were other examples but I fear this is long enough as it is. Any information would be appreciated as I finally caved in and updated my girlfriends iMac because I was not happy leaving it on old security updates for so long. She is not at all pleased.

We have two times:
Hardware Overview:

Model Name: iMac
Model Identifier: iMac8,1
Processor Name: Intel Core 2 Duo
Processor Speed: 2.66 GHz
Number Of Processors: 1
Total Number Of Cores: 2
L2 Cache: 6 MB
Memory: 2 GB
Bus Speed: 1.07 GHz
Boot ROM Version: IM81.00C1.B00
SMC Version: 1.29f1

Mac OS X (10.5.6)

Posted on Feb 26, 2009 1:54 PM

90 replies

James Snook Author

Level 1

12 points

Mar 6, 2009 10:57 AM in response to James Snook

Sorry to have left the topic for this long, I said I would look into some suggestions and I do mean to, busy with shift work for the time being.

Just an aside though, many of the things I have managed to glance at so far really appear to not be related to the O.P. topics. Specifically not being limited to web browsing. Will be back after the work cycle ends.

(I do not intend to be one of those people who asks a question then never replies with results)

iBod

Level 7

29,345 points

Mar 6, 2009 11:06 AM in response to James Snook

Hi James,

When you do get a chance to go over things, I know you doubt they'll work, but do try the OpenDNS settings just to discount them if nothing else.

James Snook Author

Level 1

12 points

Mar 6, 2009 11:09 AM in response to iBod

Been troubleshooting as a job since I was 16, I intend to discount nothing 😉

Currently I have IPv6 off, but as with last time I did that, no effect.

Mar 6, 2009 11:16 AM in response to James Snook

He specifically mentioned Safari!

James Snook Author

Level 1

12 points

Mar 9, 2009 8:14 PM in response to James Snook

Ok, having turned off DHCP and added the two OpenDNS servers I will see how it fairs over the next few days, as I rebooted having done so and the regular issues never arose immediately post reboot I found. Working right now, but as of yet this is not an indication towards anything.

Should this actually work, and my local DNS on my router no longer be "good enough" post .5.6 update I would be rather angry. As I imagine would the many other people who suddenly had useless internet connections. Asking the average consumer to meddle with their IP settings usually will not end well.

Mar 10, 2009 3:35 AM in response to James Snook

I am not sure why you have moved away from DHCP. I prefer local fixed IPs for mine and my wife's wired connections but I expect other members of the family to use DHCP with their wireless connections. I have only noticed a very small connection time difference.

Your computer will only ever use your first DNS server unless it stops working. I find that it is normally best to use the latest DNS server recommended by your ISP. These do change from time to time so it is worth checking for their latest recommendation.

For many years my Macs have often performed better after a change of DNS server. I suspect this is caused by repopulating the DNS etc caches with recent routes which is why I now use the following with Lingon to clear the DNS cache at startup:

dscacheutil -flushcache

I restart my Macs at least once a day.

James Snook Author

Level 1

12 points

Mar 10, 2009 8:58 AM in response to Neville Hillyer

You would think that if I could run 10.5 all the way to 10.5.5 for days on end, never once encountering any sort of networking problem, then only when running 10.5.6 that it would not be an issue that required frequent flushing of anything. I removed DHCP in order to forcefully remove my router supplied DNS server, so as to make the OpenDNS ones the only ones in the list. Otherwise it does not allow you to remove the supplied one.

I have never had a cause to reboot a mac more than once a week, excluding the obvious updates or big system changes.

Thus far OpenDNS has been nice and fast, but as stated the problem rarely arose for me in the first hours post reboot.

Mar 10, 2009 10:06 AM in response to James Snook

Unless I am mistaken you should be able to select DHCP in Network preferences and still assert any DNS server you wish.

I am aware that many people don't like booting very often. Whilst I keep servers running 24/7 I have never seen the point of keeping desktops running especially as, in my experience, Macs are more responsive if regularly rebooted.

I am sorry you have experienced these difficulties but occasionally OS X misbehaves and only a reinstall resolves the problem. I have such a problem with one of my G4s - it works well but permissions repair takes 3 hours. I know there is something wrong as another identical G4 takes only 30 minutes.

James Snook Author

Level 1

12 points

Mar 10, 2009 10:15 AM in response to Neville Hillyer

Done all of those things, multiple times. As stated in the first post I put 10.5.5 back on and everything was solved. Did 10.5.6, all broke. Format again, tried with the combo update, all broke.

It is 10.5.6 alone, with much evidence, for whatever cause inside.

Anyway, running 24/7 with ample use of sleep. We use these computer on and off every day, why prolong the wake time.

Mar 10, 2009 12:26 PM in response to James Snook

Are these iMacs within their guarantee period? If so perhaps you should return them to Apple.

I note that you are not keen on moving away from your local DNS and I can understand your position but it is one thing which is slightly unusual.

Have you played with your hosts file or is it as supplied by Apple?

How easy is it to remove some RAM? It is a long shot but a few years ago an Apple software glitch (which they were slow to own up to) had unfortunate consequences for Intel Xserves with 2 GB or more of RAM.

James Snook Author

Level 1

12 points

Mar 10, 2009 1:50 PM in response to Neville Hillyer

I did in the first post make clear the problem is identical to that noted by many other people, and in one specific case about 190 networked university machines. I think the chance of these two being defective is not so high.

Every previous software version I have used from 10.3.x to 10.5.5 has been a non issue, and remains so. As has been the case for the other cases I had read about since 10.6.6 has been put out.

I believe in that case the ram, stock 2GB from last refresh in 2008 is a non issue. If it is, 10.6. 6 is still the problem, not the hardware.

OpenDNS has been in use on this machine for about 17 hours now, still performing well but starting to show signs of internet retrieval time lag. I imagine tomorrow night will show one way or the other if it is helping. I need to go read the document linked earlier on JungleDisk, had not had time so far.

James Snook Author

Level 1

12 points

Mar 10, 2009 3:51 PM in response to Dogcow-Moof

So having read that, no. I do not think the jungle disk explanation clears up anything. They talk about 10.4.x to 10.5.x where I am talking 10.5.0/5 being fine and 10.5.6 alone being a problem. It would seem that topic covers fundamental differences from .4.0 to .5.0.

Mar 11, 2009 10:01 AM in response to James Snook

I suspect your problem would go away if you were to only cache DNS on the Macs (ie not on your router) and arrange for the cache to be cleared at least once a day.

I would be the first to agree that this should not be necessary but in my experience this has always improved Mac performance - not only OS X.

The performance boost from this is greater with modern faster networks which resolve DNS queries very quickly.

I also use a hosts file to block adverts which have dramatically slowed the web in the last year.

James Snook Author

Level 1

12 points

Mar 12, 2009 3:37 AM in response to Neville Hillyer

My only question then is why would this help? It is not an option I can actually try, but I am interested to know the reason. 7 other devices with absolutely no problems at all, and two iMacs with no problems at all, unless they use 10.5.6.

I know I keep repeating the stated issue here but I am just not seeing how the router/dns could be responsible.

What I am getting at perhaps is what has changed between 10.5.5 and 10.5.6? So far I have seen nothing to answer that specific question.

Mar 12, 2009 4:21 AM in response to James Snook

James

I wish I knew the answer to this and several other Mac performance issues. I can only say what I have tried and found to work.

I am unclear why you say: "It is not an option I can actually try".

Not all Macs use the same code.

Since you have tried so many things and are still unhappy I think it would be in your best interests to get Apple involved via the guarantee. After all it is their hardware and software which is at fault.

On a probably unrelated point I have recently been investigating the considerable variation in permissions repair times. It occurs to me that this could be related to the combination of Apple not removing redundant items from the database (ie it grows with installation history) and a change in default operation between sqlite2 and sqlite3 requiring more disk cycles for every item in the database. Sqlite is being used more and more and I would expect this to affect at least Firefox 3 and Safari as well as permissions repair. In theory this exceptionally slow behaviour can be modified with sqlite pragma statements but I have not yet found a way that users can get these pragmas to persist. To date the only practical workarounds I have found are to turn off browser 'fraudulent sites' and do a clean reinstall followed by the latest manual combo update. These workarounds work independently, ie you can get the benefit of one without doing the other.

Can I assume that you have already followed my advice to turn off fraudulent sites in Firefox 3 and Safari?

10.5.6 causing terribly slow Internet access