Ars has the details. Bottom line? The thermal design power (TDP) rating of the Core 2 Duo (ie, Merom) T7600 (2.33 GHz, 4 MB cache) is 34W, just 3W greater than the Core Duo (ie, Yonah) T2700 (2.33 Ghz, 2 MB cache).
Remember that Merom is pin-compatible with Yonah, so if you buy a Yonah laptop* today you can swap in Merom later. All the recent sturm und drang about Microsoft’s decision to limit HD-video playback to only 64-bit devices is therefore rather overwrought.
For anyone in the market for a notebook, my updated advice is to go ahead and buy a Yonah-based laptop now rather than wait. As usual I recommend NoteBookReview.com for buying advice, though you are also welcome to leave a comment if you’d like to solicit my opinion on a given machine.
NBR also has a piece on the Merom launch, which includes a most recent list of available models with Core 2 duo from the major manufacturers. And, because not all laptop manufacturers are shipping Core Duo-based laptops with the correct settings in Windows XP to take full advantage of the dual-core performance, they also have a registry hack that all Yonah/Merom owners need to make sure is in place. I’ve reproduced it below the fold.
*if the motherboard uses Intel’s 945 Express chipset.
1. Go to Start Menu > Run. Type “Regedit” and press Enter.
2. The registry location: “HKEY_LOCAL_MACHINESYSTEMCurrentControlSetControlSession Manager” should have a key named “Throttle” there, if not make it by right clicking, point at “New > Key… name it Throttle.
3. Still in the registry, in the right panel inside the Throttle key should be a DWORD called “PerfEnablePackageIdle” with the value of 1. If not there, right click, point to New > DWORD and name it “PerfEnablePackageIdle”. Type 1 in the Value data box (as hexadecimal) to enable the performance state policy behavior to increase performance.
4. Quit Registry.
5. Now you need to look at your boot.ini file to make sure that the command /usepmtimer is there. You can do this by Right Clicking on the “My Computer” icon, then go to Properties, click on the ADVANCE tab, then under Startup and Recovery click on “Settings”, then click on EDIT. Make sure your boot.ini has the “/usepmtimer” in there (located in the very last line), if NOT then just copy and paste the below in there or type the /usepmtimer as the very last item of text so it reflects what you see below:BOOT.INI example
[boot loader]
timeout=30
default=multi(0)disk(0)rdisk(0)partition(1)WINDOWS
[operating systems]
multi(0)disk(0)rdisk(0)partition(1)WINDOWS=”Microsoft Windows XP Professional” /noexecute=optin /fastdetect /usepmtimer6. Restart your computer.
The two chips may be pin-compatible, but in order to take advantage of the newer chip you might need a bios upgrade which might not be available for any given model. Is the difference in cache size the only difference between them?
You’ll almost definitely need a bios upgrade, but I would be very surprised if those are not widely available. Dell will definitely offer them, which pretty much guarantees everyone else has to follow suit.
The major difference between Yonah and Merom is that the former is 32 bit and the latter 64 bit, of course, which means that until we see 64-bit-optimized apps from the software companies, any performance improvement will likely be incremental rather than a leap ahead. Yonah was arguably a leap ahead of Dothan (aka the Pentium M) because of the dual-core architecture – you basically got twice the CPU for the same thermal envelope and power draw, which is really remarkable. Compared to Dothan, Yonah was a have-your-cake and eat-it-too situation. Merom will be more of a forward-looking upgrade.
Beyond the bits, the cache size is one difference and I think that the execution pipeline in Merom is longer.
But the exciting thing about Merom in my mind is that I personally see it as a better chip than Conroe. Remember Conroe is the desktop 64 bit dual core chip, that was just released (and blows the Athlons away, much to sharikou’s disappointment). What I want to see is desktop “silent” PCs running on the Santa Rosa platform, with the next-generation storage solutions that I mentioned earlier. Conroe will always be king of the hill for raw performance but we are going to see a blurring of the line between “desktop” and “portable”. The enthusiast term for this is “mobile on desktop” and I plan to write about this more soon.