Hello, I'm new to this forum, so please excuse me if I use the wrong terminology, or show up my lack of knowledge in the subject of keeping time. Please also excuse the length of this message, but I thought it would be best to explain, as much as I can, the set up here and the problems that I am hoping someone might be able to help me out with. Up until recently I just used programs like Dimension 4 to periodically check and, if necessary, adjust my PC Clock to bring it back in line with the publically available SNTP or NTP time servers. This seemed to work OK for general Amateur Radio use, such as making sure that I was transmitting and receiving the WSJT modes at about the right time each minute or 30 seconds. It was also good enough for logging programs as well, of course. However, a friend of mine developed an SSTV program which calibrated the soundcard output against the PC clock, and had a routine built in which would check the clock against one or other of the (S)NTP time servers and adjust the clock if it was out of step. I sould say, upfront, that neither of the following PCs is 'overclocked' and, to the best of my knowledge, have not had any modifications made to the motherboards. I have two PCs permanently connected to the internet (via two different ISPs, telephone lines, WiFi routers etc.) and the older one, which has an ABIT motherboard in it, I think, seems to keep time reasonably well. It's not brilliant, but Tardis says that it has a daily drift of about 0.054 seconds per day and NTPmonitor shows that the maximum error, usually against time.apple.com, is something like +500 milliseconds every couple of hours. Against the stratum 2 clock that John (N8UR) runs, it is much better and there are not the 'spikes' of +500 milliseconds against his time server, nor are the 'spikes' seen in comparison with a couple of other publically available servers. This PC has a 'hard life' being the one that I install any program that takes my fancy, is used for email and general internet surfing, is connected to an older WiFi unit and to the slower of the two ISP connections. The other PC has recently been reformatted, Windows XP reinstalled (I had tried to use it with an SDR radio, but gave up on that about a year ago and I had changed a few things in XP that I could not remember how to undo again) it has a newer ABIT motherboard, a KN8, has a faster processor than the older machine and is only used for programs connected with either running a radio using CAT control, or programs which run SSTV/WSJT modes through a soundcard. I recently removed an M-Audio D44 soundcard board, in case that was part of the problem, but there's been no difference, that I can see, with the time keeping problems on this newer PC. This second PC is a real pain when it comes to keeping it on time. About every hour any program which is set up to correct the clock (such as Tardis, D4 or the SSTV program mentioned before) detects that the clock is up to +1.5 seconds out, however, in the next period it is almost the same value out in the other direction! If I leave NTPmonitor running, without any correction, I see the +1.5 second 'glitch' but then the PC clock settles back onto reasonably good time keeping, which I think is why the automatic adjustment systems carry out a plus followed by a minus correction. Tardis calculates the estimated daily drift at about -83 seconds per day and NTPmonitor shows a deviation, from many of the various time servers, of up to 2 seconds at times, and quite often 1.5 seconds. However, if I turn on the adjustment system, I get the +1.5/-1.5 second ajustment effect. Other than scrapping the newer PC, or fitting a very expensive add on unit, can anyone think of a way of tameing this errant PC clock please? Thanks for any help. In fact, having this PC clock problem has made me read up on the subject of time and the PC Clock. :-) Dave Ackrill (G0DJA)

David Ackrill wrote: > Hello, > > I'm new to this forum, so please excuse me if I use the wrong > terminology, or show up my lack of knowledge in the subject of keeping > time. Please also excuse the length of this message, but I thought it > would be best to explain, as much as I can, the set up here and the > problems that I am hoping someone might be able to help me out with. > > Up until recently I just used programs like Dimension 4 to periodically > check and, if necessary, adjust my PC Clock to bring it back in line > with the publically available SNTP or NTP time servers. This seemed to > work OK for general Amateur Radio use, such as making sure that I was > transmitting and receiving the WSJT modes at about the right time each > minute or 30 seconds. It was also good enough for logging programs as > well, of course. > > However, a friend of mine developed an SSTV program which calibrated the > soundcard output against the PC clock, and had a routine built in which > would check the clock against one or other of the (S)NTP time servers > and adjust the clock if it was out of step. > > I sould say, upfront, that neither of the following PCs is 'overclocked' > and, to the best of my knowledge, have not had any modifications made to > the motherboards. > > I have two PCs permanently connected to the internet (via two different > ISPs, telephone lines, WiFi routers etc.) and the older one, which has > an ABIT motherboard in it, I think, seems to keep time reasonably well. > It's not brilliant, but Tardis says that it has a daily drift of about > 0.054 seconds per day and NTPmonitor shows that the maximum error, > usually against time.apple.com, is something like +500 milliseconds > every couple of hours. Against the stratum 2 clock that John (N8UR) > runs, it is much better and there are not the 'spikes' of +500 > milliseconds against his time server, nor are the 'spikes' seen in > comparison with a couple of other publically available servers. This PC > has a 'hard life' being the one that I install any program that takes my > fancy, is used for email and general internet surfing, is connected to > an older WiFi unit and to the slower of the two ISP connections. > > The other PC has recently been reformatted, Windows XP reinstalled (I > had tried to use it with an SDR radio, but gave up on that about a year > ago and I had changed a few things in XP that I could not remember how > to undo again) it has a newer ABIT motherboard, a KN8, has a faster > processor than the older machine and is only used for programs connected > with either running a radio using CAT control, or programs which run > SSTV/WSJT modes through a soundcard. I recently removed an M-Audio D44 > soundcard board, in case that was part of the problem, but there's been > no difference, that I can see, with the time keeping problems on this > newer PC. > > This second PC is a real pain when it comes to keeping it on time. > About every hour any program which is set up to correct the clock (such > as Tardis, D4 or the SSTV program mentioned before) detects that the > clock is up to +1.5 seconds out, however, in the next period it is > almost the same value out in the other direction! If I leave NTPmonitor > running, without any correction, I see the +1.5 second 'glitch' but then > the PC clock settles back onto reasonably good time keeping, which I > think is why the automatic adjustment systems carry out a plus followed > by a minus correction. Tardis calculates the estimated daily drift at > about -83 seconds per day and NTPmonitor shows a deviation, from many of > the various time servers, of up to 2 seconds at times, and quite often > 1.5 seconds. However, if I turn on the adjustment system, I get the > +1.5/-1.5 second ajustment effect. > > Other than scrapping the newer PC, or fitting a very expensive add on > unit, can anyone think of a way of tameing this errant PC clock please? > > Thanks for any help. In fact, having this PC clock problem has made me > read up on the subject of time and the PC Clock. :-) > > Dave Ackrill (G0DJA) > > Dave Are you sure that the newer PC isnt changing its cpu clock speed in response to its perceived load? Most modern PCs have this capability which may or may not be able to be disabled via the bios. Automatic adjustment of the clock rate to minimise power is incompatible with accurate timekeeping. Bruce

Bruce Griffiths wrote: > > Automatic adjustment of the clock rate to minimise power is incompatible > with accurate timekeeping. > Thanks for the responce Bruce, I don't think the newer PC has that facility, and the load on it is not all that great normally. The CPU usually reports well under 50% utilisation, and I only run 3 applications most of the time. One being the CAT control of the radio, the other is the Data Modes program, which runs SSTV/PSK/RTTY etc., and NTPmonitor. I'll Google to see how I can find out if the newer PC (newer being relative, it's over a year old now) has the sort of system that you mention running on it. Thanks - Dave (G0DJA)

David Ackrill wrote: > Bruce Griffiths wrote: > >> Automatic adjustment of the clock rate to minimise power is incompatible >> with accurate timekeeping. >> > > Thanks for the responce Bruce, > > I don't think the newer PC has that facility, and the load on it is not > all that great normally. AH! It does have a utility calld "Cool n' Quiet, and it seems that can only be dissabled in the BIOS, from what I have read. I also have installed the RightMark CPU Clock Utility, to try and get a grip on what is going on. Throttling seems to be enabled, the difference between the Core Clock and the 'Throttle' seems not that great. Also, the older machine (running Windows 2000 pro) also seems to have Cool n' Quiet on it, so I'm wondering if this is having such a great effect on the XP machine? Anyway, at least I know more about the motherboards and operating systems in both my PCs now. :-) Dave (G0DJA)

David Ackrill wrote: > David Ackrill wrote: > >> Bruce Griffiths wrote: >> >> >>> Automatic adjustment of the clock rate to minimise power is incompatible >>> with accurate timekeeping. >>> >>> >> Thanks for the responce Bruce, >> >> I don't think the newer PC has that facility, and the load on it is not >> all that great normally. >> > > AH! It does have a utility calld "Cool n' Quiet, and it seems that can > only be dissabled in the BIOS, from what I have read. > > I also have installed the RightMark CPU Clock Utility, to try and get a > grip on what is going on. > > Throttling seems to be enabled, the difference between the Core Clock > and the 'Throttle' seems not that great. > > Also, the older machine (running Windows 2000 pro) also seems to have > Cool n' Quiet on it, so I'm wondering if this is having such a great > effect on the XP machine? > > Anyway, at least I know more about the motherboards and operating > systems in both my PCs now. :-) > > Dave (G0DJA) > Dave If only the application/utility made use of the so called high precision timer available in all recent motherboard chipsets. This timer doesnt have the resolution achievable by counting cpu cycles, however at least its clock frequency is constant. See: http://en.wikipedia.org/wiki/SpeedStep Where it explains why Windows2000 may not throttle the cpu back whereas XP is more likely to do so. Disabling XP's use of Speedstep is a slightly trickier: http://www.bay-wolf.com/speedstep.htm Bruce

David Ackrill wrote: > > Anyway, at least I know more about the motherboards and operating > systems in both my PCs now. :-) Don't they say that pride comes ahead of a fall? I decided to get rid of my errant XP machine, and it was sort of working OK, so I reinstalled Windows XP and went out to reinstall the NeForce drivers again... Now Windows XP has decided that it wont let me do that. Sorry to burden this forum, but I may be some time before I manage to get Windows XP to work properly again... Excuse me <Head:Bang> <Head:Bang> DAve (G0DJA)