MBProbe Frequently Asked Questions Copyright 1998-99 Jonathan Teh Soon Yew http://www.focus-asia.com/home/jonathanteh/mbprobe/ http://web.bham.ac.uk/jst829/mbprobe/ General ------- Q: Does MBProbe slow down my computer? A: Yes, by a little. ANY program running in the background will slow down the computer. The question is: by how much? MBProbe only polls the monitoring chips once every 5 seconds and does some trivial calculations and comparisons so the impact on system performance is negligible. You certainly won't notice it and it probably won't affect benchmarks like Winbench or Winstone either. Q: It says "Unable to open giveio.sys driver" in Windows NT/2000 and quits. I thought you said it supported Windows NT/2000. A: It does. You must install the giveio.sys driver first using NTINST otherwise MBProbe will be unable to access I/O ports. Refer to readme.txt. Q: Why does it detect my Celeron/Xeon as a Pentium II .25u? A: That's what it is. Essentially, all 3 CPUs share the Deschutes core which is a Pentium II core on .25 micron process. The difference lies in the amount of L2 cache- Celeron has 0K, Pentium II has 512K running at half core speed and a Pentium II Xeon has up to 2MB running at core speed. Q: Why does it detect my Celeron A as a Pentium II on-die L2 cache? A: That's what it is. Essentially, it is a Pentium II core on .25 micron process with the L2 cache on the same die as the CPU. There may be future Intel CPUs with such a configuration. Monitoring chips ---------------- Q: How do I know what type of monitoring chip I have? A: Check your motherboard manual or look for one on the motherboard. Quite a few motherboards manufactured since 1997 do include a hardware monitoring chip (including the popular Asus TX97 series). Most include an LM78-type chip or a Winbond chip. Newer boards may come with a Heceta II/III-type chip. QDI boards using the 440BX chipset appear to have an LM80. MBProbe should be able to detect one of these chips. If it says "None", then your motherboard probably doesn't have one of these chips. Q: I'm very sure my motherboard has a hardware monitoring chip but it still says "None". A: So it does. Check the list of unsupported chips first to see if the chip in your motherboard is listed there. If it is, you're out of luck. If not, it may be that your chip isn't where MBProbe expects it to be. The LM78-type chips are searched for at ISA port 290h. Other hardware monitoring chips are searched for at SMBus address 28h-2fh. Chips at other ports/addresses will not be found. If you have such a configuration, try to find out the address of the chip and contact me with the information. SMBus monitoring chips are slave devices and as such need a supported SMBus host. At present the only SMBus host supported is the Intel PIIX4. Voltage ------- Q: Why are there two Vccp readings? A: That's what the monitoring chip supports. You might have to disable one if if it shows an incorrect reading. On my Asus P2B, they're both the same. Presumably dual processor boards have one reading for each processor. Q: Why are some of the voltage readings/adjustments disabled? A: Some monitoring chips do not support certain readings. E.g. LM78-type chips are normally not setup to monitor +2.5V. Q: Why can't I enable warnings for both Vccp2 and -12V? A: You have a Heceta 2 monitoring chip. The Vccp2 and -12V readings are read from the same location hence only one of the readings would make sense. This depends on what the motherboard manufacturer actually connected to that input. Intel boards seem to have it connected it to -12V. Q: It displays my CPU voltage as 0.00V. What's wrong? A: Chances are your CPU is either too old or too new. In particular, CPU voltages for 486 and early Pentium 60/66 CPUs are not in the program since it is assumed that motherboards supporting CPUs that old would not be equipped with a hardware monitoring chip. The other case is that the CPU is too new and MBProbe has not been updated yet to take this into account. Please e-mail me with full details of your processor (manufacturer, model, clock, voltage) and I will update MBProbe. Q: It detects my CPU voltage incorrectly. What effect does this have? A: This is harmless; simply select the correct CPU core voltage in the 'Voltage' tab. MBProbe guesses the CPU voltage via its CPUID. This is basically the information you see under 'CPU information' on the 'General' tab in Properties. The problem with this is that the CPUID doesn't always differentiate every single variant of a particular CPU. The following table identifies the correct (non-mobile) CPU voltages (variants which confuse MBProbe are marked as such): Cyrix 6x86 : 3.52V } Cyrix 6x86L : 2.8V } identical CPUID Cyrix 6x86LV : 2.45V } Cyrix 6x86MX/MII : 2.9V AMD 5k86 : 3.52V AMD K6 PR233 : 3.2V } AMD K6 (model 6) : 2.9V } identical CPUID AMD K6 (model 7) : 2.2V AMD K6-2 : 2.2V AMD K6-2 400/450 : 2.4V AMD K6-III : 2.4V IDT WinChip C6 : 3.3V (std), 3.52V (VRE) IDT WinChip 2 : 3.3V (std), 3.52V (VRE) Intel Pentium : 3.3V (std), 3.52V (VRE) Intel Pentium MMX : 2.9V Intel Pentium Pro : 3.3V Intel Pentium II .28u : 2.8V Intel Celeron : 2.0V Intel Pentium II .25u : 2.0V Intel Pentium II Xeon : 2.0V Intel Pentium III : 2.0V Intel Pentium III Xeon: 2.0V Note that AMD K6 chips could be operating at any of the 3 voltages shown above (indeed there are certain PR233 models operating at 2.9V). The only way to be sure is to physically remove the CPU from its socket and look for the voltage printed on it. Q: The voltage readings are screwed. What's wrong? A: This is due to some motherboard manufacturers connecting different voltages to the monitoring chips. Refer to the known issues section in the readme. Please report your complete set of readings (from MBProbe and another source such as the BIOS, in the original order), motherboard model and I will try and correct it. For the time being, disable the warnings. Temperature ----------- Q: Why is the default temperature display in Fahrenheit? A: It is the default only if your regional settings (in the Control Panel) is set to English (United States). Many people forget to change the regional settings when installing Windows. Just change the temperature display to Celsius if you like. Q: Why do the temperature readings show -48C? A: You probably have a Winbond chip. The two -48C readings are coming from external temperature inputs which are unconnected. You need to get two thermistors (NTC type, 10Kohm @ 25C, B-value 3435) and connect them to the corresponding pins on the motherboard. On my Asus P2B, they are labeled JTCPU and JTPWR which correspond to the 'CPU' and 'Aux' readings respectively. Visit your local electronics hobbyist store for the thermistors or ask the dealer where you purchased your motherboard from. Q: Why do I get the same readings from the LM75:0, 1 and W8378xx:2, 3? A: The Winbond chips simulate two LM75s (W83783S simulates 1 only) and as such gives identical readings to its own 2nd and 3rd temperature inputs. Q: What's the difference between using MAX1617:x and MAX1617:xR? A: The MAX1617 (and similar chips like the MAX1617A and ADM1021) have 2 temperature registers. The first one (without the R) is the local or on-die temperature which is the temperature of the chip itself. The second one (with the R) is the remote temperature which measures the temperature of a remote diode connected to it. The Pentium II contains such a diode and is can be connected to the MAX1617. Hence, the 'R' reading is the CPU temperature and the non-'R' reading can be used as an extra motherboard temperature reading. Q: What should the correct CPU temperature offset be? A: Good question. The best way is to check the temperature in the BIOS and compare it with the temperature reported by MBProbe. Take the difference as the offset value. As a guide, these are the figure reported by other people (all figures in degrees Celsius): AMD 5k86 PR133 : + 8 AMD 5k86 PR166 : +17 AMD K6 PR166 : + 7 AMD K6 PR200 : + 7 AMD K6 PR233 : +20 AMD K6 PR300 : +20 Cyrix MII PR200 : +15 IDT WinChip C6 : +20 Intel Pentium : +32 Intel Pentium MMX : +22 Fans ---- Q: Why are some of the fan readings/settings disabled? A: Some monitoring chips do not support 3 fan inputs. Refer to the feature table in readme.txt. Also, some chips have 3 fan inputs but the divisor on the 3rd input is fixed at 2. Q: What are fan divisors for? A: The monitoring chips do not directly return the RPM of the fan directly; instead they return the number of 'counts'. As a guide, use the following divisor values corresponding to your fan's nominal RPM: Divisor Nominal fan RPM 1 8800 2 4400 4 2200 8 1100 In general, if you have a fan connected and the reading shows 0RPM, try selecting a higher divisor. Always use the lowest possible divisor that still gives a non-zero reading to ensure sufficient resolution (jumps between RPM indications). Q: Why don't my fan divisor changes take place immediately? A: Fan divisors have to be set on the hardware monitoring chip and it only takes effect the next time a reading is taken, hence the delay. Q: Why is my CPU fan displayed in the wrong place? A: Some motherboard manufacturers (Abit, Intel) have the CPU fan connected to the 3rd fan input. Just change the Fan 3 label to 'CPU'. Remember to change the Fan 2 label to something else so that the tooltip displays the correct fan speed for the CPU.