Intel Xeon L5639 – Inexpensive low-power 6C/ 12T Xeons are here!

Proxmox VE Intel Xeon on Node 3
Proxmox VE Intel Xeon on Node 3

The Intel Xeon L5639 is a Westmere-EP LGA1366 processor with a 2.13GHz base clock and up to 2.67 GHz 1-2 core turbo speeds. Looking at Intel Ark, one cannot find any reference of this processor (see here.) Being a 32nm Westmere-EP design it has 12MB of L3 cache and features lacking from the Xeon 5500 series including AES-NI for common encryption applications. The hexa-core chips are also 60w TDP parts, so are fairly easy to cool in virtually any chassis. The story today is that these chips are now very inexpensive falling from well over $200/ chip earlier this year to under $160 today. For STH users, this is going to be a significant potential upgrade. In the forums there is a thread with a decent amount of excitement around these low cost Intel Xeon L5639 chips.

More About the Intel Xeon L5639

A few quick reasons to look at the Intel Xeon L5639 over the L5520:

  1. Six cores versus four cores
  2. More on-die cache
  3. Lower idle power consumption due to the 32nm process on the L5639 versus the 45nm process on the L5520 (although higher overall TDP)
  4. Support for up to 16GB DIMMs and better support for 6 DIMMs/ CPU operation at full memory speeds
  5. 4-core turbo is 2.533GHz on the L5520. The L5520’s max speed is 2.4GHz for all four cores

One of the most popular articles on STH this year on the site was the Dell PowerEdge C6100 XS23-TY3 piece. We were looking for affordable colocation platforms and this fit the spec well. Users agreed and it also became a major discussion topic with many pages of user stories, tips and tricks and etc. on the forums. The Intel Xeon L5638 and L5639 chips proved so effective that we even employed one node of the chips for our STH colocation.

Proxmox VE Intel Xeon on Node 3
Proxmox VE Intel Xeon on Node 3

Costs in early 2013 were too high to use them in more than one node though. Interestingly enough, that node when in use has an average load that is about half as high as when we are running the main instance off of the dual L5520’s. It does make a solid case for the L5639’s which are essentially one 133MHz speed step faster and now less expensive.

Where the Intel Xeon L5639 Chips Come From

A few months ago, I was chatting with one of the common suppliers (who we did purchase one from.) The supplier told us that many or the original Dell C6100 lots had become available with the L5520 chips, which were the most common selling for very low prices. At the time, the latest Facebook de-commission had Intel Xeon L5639 processors installed in the various C6100 nodes. These were not processors generally marketed at retail, but were made for OEMs such as Dell and HP. Much like we learned this week that Facebook and ebay can get custom chips from Intel, so can big OEMs. Since the Dell C6100 was selling well with low cost Xeon L5520 processors, vendors were removing the eight included processors which sold for $250 each ($2,000 total), replacing them with L5520’s, and selling complete Intel Xeon L5520 C6100’s for under $800. That is where we saw the value of recycling the L5520.

A prediction from that time period was that these Intel Xeon L5639 processors would flood the market at some point. That time is rapidly approaching. From approximately $250 per chip three months ago, these processors are selling for under $160 now making them a great value.

Where to Find Them

Here is an ebay search for the Xeon L5639. One should be careful as the “production” chip is a SLBZJ spec. There are engineering samples on ebay so it does warrant a buyer double-checking the spec code.


  1. Which motherboards are recommended for a home server using these CPU’s if one isn’t interested in C6100 nodes?

  2. The Xeon 5xxx series processors have a very mature ecosystem at this point. May be worth highlighting requirements in the forums for a best-fit/ value. What is the best may include other features like SAS controllers and additional NICs for example.

  3. I would recommend the Supermicro X8ST3-F or X8STE-F. These two are very similar but the ST3 model includes a 3Gb SAS controller which is obsolete but you may be able to find a deal on one.

  4. This is very good news as I’ve been waiting for six-core CPUs spread on the market. I’m expecting to get them at low cost so that I can economically configure server with other parts soon.

  5. Hi,

    Did anyone tested this SLBZJ processors on HP servers ? I got a 380G6 and 360G6 and i would sure consider upgrading both servers processors from E5530 to this awesome L5639 as long as it works. Are there any possible problems with them as being engineering samples ? Is there a different spec for this model that is not a engineering sample ?

    Thank you in advance.

  6. @Alexandru: SLBZJ are not engineering samples, those are production versions. Engineering samples are Q4U2 specced and are better be avoided.

  7. Thank you very much for your answer Mauri. I did order two SLBZJ and waiting to test them on a DL380 G6 and DL360 G6.

  8. I got one of these L5639 in a asus sabertooth x58 board overclocked to 3.5GHz on air with 48GB ram. Very good cpu for the price. Beats a i7-970 when overclocked easily.


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