You need the thermal pad because without it, there's a gap between the heatsink and the chip. And no, it's not a mere GPU, it's the Intel GM965 northbridge chip which contains the following:
* memory controller (DDR2)
* integrated graphics (Intel GMA X3100)
* PCI Express links for the WLAN, WWAN slots, LAN and Firewire Controller
* Front-side bus (communication link to the processor)
* dedicated link to the ICH8M southbridge chip (which handles SATA, USB, and other devices)
Regarding undervolting:
From experience, The Core 2 Duo T7xxx processors run hotter and don't undervolt as much compared to the later T8xxx CPUs.
I have a Linux CPU undervolting guide here:
viewtopic.php?t=128707#p834379
Looks like linux-phc.org is gone for good. Fortunately, I have a local copy of read_msr. It's a python program that reads the processor's Model Specific Registers (MSR) to show various data relevant to undervolting, including:
Current Frequency ID (FID) and Voltage ID (VID)
Target FID and VID -- this refers to the FID and VID you were aiming for. i.e. set in
/sys/devices/system/cpu/cpu*/cpufreq/phc_controls .
I copy-pasted the contents of said python program.
Code: Select all
#!/usr/bin/env python
#This is an Interface to the MSR device.
#To use this the kernel module "msr" needs to be loaded.
#It gets the actual VID and FID and the target VID and FID
# Licence: GPL
# 2008,2009 cmichael/the-fallen
from time import sleep
import os, sys
###some offsets
MSR_IA32_PERF_STATUS=int(0x198)
MSR_IA32_PERF_CTL=int(0x199)
MSR_IA32_ABS_VAL=int(0xce) #absolute Minimum(SLFM) and Maximum(IDA) Values stored here
MSR_IA32_MISC_ENABLE=int(0x1a0) #some features are stored here - not well known to us
MSR_IA32_MISC_ENABLE=int(0x1a0) #some features are stored here - not well known to us
MSR_FSB_FREQ=int(0xCD); #an Index of possible FSB's is stored here
INTEL_FID_MASK = int(0x1f) #00111111 - first 5 Bits define the FID
INTEL_DID_MASK = int(0x40) #01000000 - 2nd highest Bit defines the DID
INTEL_HID_MASK = int(0x80) #10000000 - highest Bit defines the HID
INTEL_VID_MASK = int(0x3f) #bit 7 and 8 are reserved, Bits 1-6 are VID
INTEL_MISC_IDA_MASK=int(0x40)
INTEL_MISC_EIST_MASK=int(0x01)
INTEL_MSR_FSB_MASK=int(0x07) #first three bits are intex of a FSB
READMSR_VERSION= "0.2pre-3"
"""
Table found on :
Intel 64 and IA-32 Architectures
Software Developers Manual
Volume 3B:
System Programming Guide, Part 2
"""
FSB_TABLE= { #dict with values: index:(CPU BUS Rate, FSB Value)
5: (100,400), #101 Binary
1: (133,533), #001 Binary
3: (167,667), #011 Binary
2: (200,800), #010 Binary
0: (267,1067), #000 Binary
4: (333,1333), #100 Binary
6: (400,1600) #110 Binary
}
class msr_interface():
basepath = '/sys/devices/system/cpu/'
iface_afids = 'phc_available_fids'
iface_versn = 'phc_version'
sysfs_maxfq = 'cpuinfo_max_freq'
sysfs_minfq = 'cpuinfo_min_freq'
sysfs_trlat = 'cpuinfo_transition_latency' # transition latency in nanoseconds
def __init__(self):
print "MSRTOOL V"+READMSR_VERSION+" started...\n"
if len(sys.argv) < 2: #no parameters given - print helpline
self.print_help()
elif sys.argv[1] == "--cpuinfo": #print available fids from interface
self.prepare_run()
self.print_cpuinfos()
elif sys.argv[1] == "--availfids": #print available fids from interface
self.prepare_run()
self.print_availfids()
elif sys.argv[1] == "--readmsr": #print msr data
self.prepare_run()
self.print_msrinfo()
elif sys.argv[1] == "--cvolt": #convert a given VID to a Voltage
self.prepare_run()
self.convert_vid() #sys.argv[2]
elif sys.argv[1] == "--fsb": #try to get FSB from MSR
self.prepare_run()
self.print_fsb()
else:
self.print_help()
def prepare_run(self):
#check if we meet all conditions (msr loaded, etc) and try to fix problems
#cody partitially taken from hw_pstaty_ctrl.py by DavidG
if not os.path.exists('/dev/cpu/0/msr'):
print "trying to load msr module"
try:
print os.popen('modprobe msr').read()
except:
print "unable to load msr module"
sleep(0.5)
#check again
if not os.path.exists('/dev/cpu/0/msr'):
sys.exit(0)
if not os.path.exists(self.basepath):
print "Unable to find sysfs directory: "+self.basepath
sys.exit(0)
if os.geteuid() != 0:
print "You need to be root to run this function. Please re-run with sudo or as root."
sys.exit(0)
def print_help(self):
print "MSRTOOL V",READMSR_VERSION
print "This Tool belongs to www.linux-phc.org and is licensed under GPL\n"
print "Usage:"
print sys.argv[0]," <function> <[arguments]>"
print "Functions may be:"
print "\t--cpuinfo : print information about available CPUs"
print "\t--availfids : print out all available fids [needs phc-intel >= 0.4]"
print "\t--readmsr : print out some interesting register values"
#print "\t--cvolt [VID] : convert the VID to a voltage value"
print "\t--fsb : read FSB and CPU Bus Clock rate"
print "\t--help : print out this help"
def print_fsb(self):
#Read the Index of FSB from MSR
for f in os.listdir(self.basepath): #iterate the sysfs directory
pathname = os.path.join(self.basepath, f) #
if os.path.isdir(pathname+'/cpufreq'): #Just to make sure its a cpu-directory
cpustring = str(f) #String of CPU (like "cpu0")
cpunr=cpustring[3:] #Number of the CPU (like "0")
if self.cpu_have_msr(cpunr): #msr interface found?
try:
msrfile = os.open("/dev/cpu/"+str(cpunr)+"/msr", os.O_RDONLY)
except:
print "Cannot read file \"/dev/cpu/"+str(cpunr)+"/msr. Are you root?"
return
os.lseek(msrfile, MSR_FSB_FREQ, 0); ##jump to where the value is
value = os.read(msrfile, 8) ##read 1 byte
fsb_index = (ord(value[0]) & INTEL_MSR_FSB_MASK)
print "[cpu%s] CPU Bus Speed: %sMHz , FSB: %s" %(cpunr, FSB_TABLE[fsb_index][0], FSB_TABLE[fsb_index][1])
os.close(msrfile)
else:
print "CPU "+cpustring+" is having no msr interface."
return
def print_availfids(self):
for f in os.listdir(self.basepath): #iterate the sysfs directory
if os.path.isdir(self.basepath+f+'/cpufreq'):
print f
phcver = self.get_phcver(f)
if int(phcver[0]) == 0 and int(phcver[1]) < 4:
print "Your PHC Version is < 0.4 - the available_fids interface is not supported"
else:
filename = self.basepath+f+'/cpufreq/'+self.iface_afids
if os.path.exists(filename):
print "\VIDs: ",int(os.popen('cat '+filename).read().strip())
else:
print self.iface_afids+" not found. But it should be available in your phc version. Strange..."
def convert_vid(self):
print "Function not yet supported. "
def print_cpuinfos(self):
#what to display: CPU type, CPU Date (stepping), Max Freq,
for f in os.listdir(self.basepath): #iterate the sysfs directory
if os.path.isdir(self.basepath+f+'/cpufreq'):
print f
filename = self.basepath+f+'/cpufreq/'+self.sysfs_maxfq
if os.path.exists(filename):
print "\thighest frequency: ",int(os.popen('cat '+filename).read().strip())/1000,"MHz"
filename = self.basepath+f+'/cpufreq/'+self.sysfs_minfq
if os.path.exists(filename):
print "\tlowest frequency: ",int(os.popen('cat '+filename).read().strip())/1000,"MHz"
filename = self.basepath+f+'/cpufreq/'+self.sysfs_trlat
if os.path.exists(filename):
print "\ttransition latency: ",int(os.popen('cat '+filename).read().strip()),"ns"
phcver= self.get_phcver(f)
if phcver[3] != "" :
print "\tPHC Version: ",phcver[0]+"."+phcver[1]+"."+phcver[2]+":"+phcver[3]
else:
print "\tPHC Version: ",phcver[0]+"."+phcver[1]+"."+phcver[2]
def get_phcver(self, cpu):
if os.path.isdir(self.basepath+cpu+'/cpufreq'):
filename = self.basepath+cpu+'/cpufreq/'+self.iface_versn
phcver=os.popen('cat '+filename).read().strip()
phcver=phcver.split('.')
major = phcver[0]
minor = phcver[1]
if phcver[2].find(':') > 0:
revision = phcver[2].split(':')
build=revision[1]
revision=revision[0]
else: #no build version
revision = phcver[2]
build=""
return [major,minor,revision,build]
def print_msrinfo(self):
#try to find cpus that are providing PHC interfaces
for f in os.listdir(self.basepath): #iterate the sysfs directory
pathname = os.path.join(self.basepath, f) #
if os.path.isdir(pathname+'/cpufreq'): #Just to make sure its a cpu-directory
cpustring = str(f) #String of CPU (like "cpu0")
cpunr=cpustring[3:] #Number of the CPU (like "0")
if self.cpu_have_msr(cpunr): #msr interface found?
msr_vals = self.read_msr(cpunr)
self.show_data(msr_vals, cpustring) #displaying data in a beautiful way
else:
print "CPU "+cpustring+" is having no msr interface."
return
def cpu_have_msr(self, cpunr):
if os.path.exists("/dev/cpu/"+str(cpunr)+"/msr"):
return 1
else:
return 0
def read_msr(self, cpu):
msr_values={}
try:
msrfile = os.open("/dev/cpu/"+str(cpu)+"/msr", os.O_RDONLY)
os.lseek(msrfile, MSR_IA32_PERF_STATUS, 0); ##jump to where current values are
value = os.read(msrfile, 8) ##read 8 bytes
msr_values['curV']=ord(value[0]) ##current voltage Identifer
msr_values['curF']=ord(value[1]) ##current FID DID HID
msr_values['hfmV']=ord(value[4]) ##HFM Voltage ID
msr_values['hfmF']=ord(value[5]) ##HFM FID DID HID
msr_values['lfmV']=ord(value[6]) ##LFM Voltage ID
msr_values['lfmF']=ord(value[7]) ##LFM FID DID HID
os.lseek(msrfile, MSR_IA32_PERF_CTL, 0); ##jump to where target values are
value = os.read(msrfile, 8) ##read 8 bytes
msr_values['tgtV']=ord(value[0]) ##target voltage Identifer
msr_values['tgtF']=ord(value[1]) ##target FID DID HID
os.lseek(msrfile, MSR_IA32_ABS_VAL, 0); ##jump to where target values are
value = os.read(msrfile, 8) ##read 8 bytes
msr_values['minV']=ord(value[0]) ##absolute minimum VID
msr_values['minF']=ord(value[1]) ##absolute minimum FID DID HID
msr_values['maxV']=ord(value[4]) ##absolute minimum VID
msr_values['maxF']=ord(value[5]) ##absolute minimum FID DID HID
os.lseek(msrfile, MSR_IA32_MISC_ENABLE, 0); ##jump to where features are
value = os.read(msrfile, 8) ##read 8 bytes
msr_values['EIST']=ord(value[2]) ##I-EST (Enhanged Intel SpeedStep enabled?)
msr_values['IDA']=ord(value[4]) ##IDA (Intel Dynamic Accelleration enabled?)
os.close(msrfile)
except:
print "Cannot read file \"/dev/cpu/"+str(cpu)+"/msr. Are you root?"
return msr_values
def show_data(self, msr_vals, cpustr):
# Displaing the data from the dictionary "msr_vals"
print "[%s] [CURRENT] FID:%s HID:%s DID:%s VID:%s " % (
cpustr,msr_vals['curF']&INTEL_FID_MASK,
int((msr_vals['curF']&INTEL_HID_MASK) > 7),
int((msr_vals['curF']&INTEL_DID_MASK) > 7),
msr_vals['curV'] )
print "[%s] [TARGET] FID:%s HID:%s DID:%s VID:%s " % (
cpustr,msr_vals['tgtF']&INTEL_FID_MASK,
int((msr_vals['tgtF']&INTEL_HID_MASK) > 7),
int((msr_vals['tgtF']&INTEL_DID_MASK) > 7),
msr_vals['tgtV'] )
print "[%s] [HIGHEST] FID:%s (HID:%s DID:%s) VID:%s (not sure if they exist here)" % (
cpustr,msr_vals['hfmF']&INTEL_FID_MASK,
int((msr_vals['hfmF']&INTEL_HID_MASK) > 7),
int((msr_vals['hfmF']&INTEL_DID_MASK) > 7),
msr_vals['hfmV'] )
print "[%s] [LOWEST] FID:%s (HID:%s DID:%s) VID:%s (not sure if they exist here)" % (
cpustr,msr_vals['lfmF']&INTEL_FID_MASK,
int((msr_vals['lfmF']&INTEL_HID_MASK) > 7),
int((msr_vals['lfmF']&INTEL_DID_MASK) > 7),
msr_vals['lfmV'] )
print "[%s] [SLFM] FID:%s VID:%s " % (
cpustr,msr_vals['minF']&INTEL_FID_MASK,
msr_vals['minV'] )
print "[%s] [IDA] FID:%s VID:%s " % (
cpustr,msr_vals['maxF']&INTEL_FID_MASK,
msr_vals['maxV'] )
print "[%s] [CURRENTLY ACTIVE FEATURES] IDA:%s EIST:%s"%(
cpustr,
int(msr_vals['IDA']&INTEL_MISC_IDA_MASK), #not sure about that
int(msr_vals['EIST']&INTEL_MISC_EIST_MASK) ) #not sure about that
print("")
msrtool = msr_interface()
So re-pasting is advisable every 3-5 years. Now there's also the question of replacing/not replacing the thermal pads! And figuring out where to source them from and of what thickness..