Intel Core 2 Duo T7600G socket: Socket M

What the Core 2 Duo T7600G is

The Intel Core 2 Duo T7600G is the unlocked twin of the T7600, released in December 2006 for one machine only. Its two 65 nm Merom cores run 2.33 GHz with the full 4 MB pool of shared L2 cache on a 667 MT/s front side bus, and 2 threads come from 2 cores with no turbo mode in this generation. The single feature that sets it apart is the freely adjustable multiplier, which turns overclocking into a ratio change instead of a base clock exercise. Intel never offered it in a retail box.

Fourteen times a 166 MHz base clock gives the stock speed, and the unlocked ratio moves up or down from there. The die matches the plain T7600 at 293 million transistors on 143 square mm of 65 nm silicon, with MMX through SSSE3 instructions, Intel 64, an XD bit, Enhanced SpeedStep, and VT-x virtualization across the board. The only sSpec is SL9U5 on the B2 stepping, with order number LF80537GF0534MU carrying the trailing U that marks the unlocked part. Voltage under SpeedStep spans 0.95 to 1.175 V on the mobile list, against 1.3 V quoted on the TechPowerUp page, another small split between the two references.

Dell is the whole story for availability. The mobile processor list notes the unlocked multiplier and names the Dell XPS M1710 as the only outlet, sold as an OEM option rather than a boxed processor. That single-chassis history matters for buyers today, because BIOS support for SL9U5 exists only where Dell shipped it, and no other vendor board lists the part. A pulled T7600G drops into any Socket M board mechanically, yet it runs only where the BIOS knows the sSpec.

Socket and motherboard compatibility

Socket M, printed mPGA478MT, is a 478-contact PGA-ZIF socket from 2006, and the T7600G uses the socketed Micro-FCPGA package throughout. The natural chipset partners are the Mobile Intel 945PM and 945GM parts that carry a 667 MT/s bus, with select PM965 and GM965 boards as rarer alternatives. In practice the board is almost always the XPS M1710 board Dell paired with this chip, since that is the only machine Intel supplied.

Compatibility outside that machine is narrow. Socket M is not electrically compatible with mobile Socket 479 despite the similar pin count, it does not fit desktop Socket 478, and it differs from Socket P by one pin location, so Santa Rosa chips are out. A different Socket M notebook board can accept the chip physically, but without a BIOS entry for SL9U5 it will not boot. Check the board vendor CPU support list before moving a pulled T7600G into another chassis.

Memory, PCIe and cooling

Memory on a T7600G system is DDR2 in two channels through the board chipset, paired as DDR2-667 SO-DIMMs on the 945PM and 945GM boards Dell used. The processor holds no memory controller, so speed, slot count, and maximum capacity all come from the chipset and the board design. The XPS M1710 board fixes those limits, and no memory choice changes the 667 MT/s front side bus between the CPU and the chipset.

No PCI Express lanes originate in the CPU. Graphics and expansion hang off the mobile chipset, which in the M1710 means a discrete mobile GPU on the board rather than anything inside the processor package. Cooling is the Dell heat pipe assembly for the exact M1710 chassis, sized for sustained load at the stock 35 W rating plus headroom Dell allowed for the unlocked ratio. Retail desktop towers do not mount to mobile sockets, and paste replacement follows the Dell service manual.

Power carries a one-watt split between references. TechPowerUp records 35 W for the T7600G and the model brief behind this batch agrees, while the mobile processor list tabulates 34 W in line with the plain T7600. This page uses 35 W and states the disagreement openly, so readers comparing the two pages see the same numbers we saw.

Upgrade paths

Clock for clock nothing on Socket M beats a T7600G, since 2.33 GHz with the full cache is the top of the socket and the unlocked ratio adds whatever the M1710 cooling allows. The plain Intel Core 2 Duo T7600 matches it at stock settings and is far easier to find, which makes it the practical substitute in any other Socket M notebook. The Intel Core 2 Duo T7400 at 2.17 GHz is the next alternative when neither 2.33 GHz part is available.

A faster mobile Core 2 Duo than 2.33 GHz needs the successor socket. Socket P arrived in 2007 with an 800 MT/s bus for Santa Rosa, and its Merom and Penryn parts need their own boards. The T7600G itself has no soldered twin and no retail channel, so the used market for M1710 boards and pulled SL9U5 chips is the only path to one.