Sandy Bridge - more on Performance in Second Life

Hi everyone, 

I've found that Lenovo has a very nice feature in their Power Manager thingie that shows you the percentage of Turbo Boost (over-clocking) that you're getting on your processor(s) and the on-chip graphics unit.  My laptop has Intel's i5-2410M, so has a nominal processor frequency of 2.3 ghz and a max of 2.9 ghz.  Its on-chip graphics unit, the HD 3000, has a nominal fequency of 650 mhz and a max of 1.2 ghz.  You can get the full specs here if you're interested:

http://ark.intel.com/Product.aspx?id=52224

As a reference point, when doing little to nothing (like now, while I'm typing this) the processor is usually idling at 34% of its nominal frequency, and the graphics is listed at 100%.  Yep, the latter seems odd to me too - but there you have it.  That value of 34% works out to a frequency of 2.3 * 0.34 = 0.782 ghz.  As a check CPU-Z reports that the cpu is at 798 mhz, or 34.08%... close enough!

So... how does this all work in SL?  Just wandering around in a sim, I usually see the processor clocked at 117% or 2.7 ghz.  In some sims, perhaps even most, its hard to be sure, the frequency of the graphics remains at a nearly constant at 100%.  I do see it blip up now and then but that's not the norm for most places.  Yet in other sims, as I walk around I see the frequency of the graphics controller go up substantially, usually to somewhere around 1 ghz, about 150% of its nominal value.  It will vary around that value, but calling it 150% of nominal is a fair average.  Also in some places if I light on a pose-ball and zoom in, the graphics frequency will go even higher up to 184% and stay there.  That works out to the maximum clock frequency for the Graphics unit of 1.2 ghz.  I haven't been able to determine why this is happening, but it's not random at all, its quite repeatable.

So that's Turbo Boost.  It seems to be working nicely in SL.  In effect I have a faster processor and graphics unit than the one I bought when needed.

But... how about the number of processors?  How many are useful in Second Life?

My conclusion on the number of processors is mixed.  First, it's pretty clear that the SL viewer code does very little to make use of multiple processors if you're just wandering around in one sim.  I see this as I look at the task manager in windows.  Since Windows treats my laptop's 2 hyper-threading processors as if they were four normal processors, it shows a utilization of about 24% to 27%.  One processor/thread's worth of work.  Its a shame, there's a lot of processing power sitting idle.

There is good news though.  When you tp from one sim to another, the viewer issues a bunch of requests for textures.  If you have a fast connection to the network, they can arrive in a burst, pouring in pretty quickly.  During this time, I've seen the utilization go up substantially and approach using all four processor threads fairly heavily.  If I turn off hyper-threading, effectively reducing the 'number' of processors that windows sees to 2, I can 'feel' the difference when tping.  It takes longer for things to rez.  And I can see the processor utilization of the two remaining processors 'peg' indicating that more power would be useful. 

So for processors, Yes, Sandy Bridge's two hyper-threading processors are useful for SL.  But only when tp-ing between sims AND you have a high speed connection to the internet. I don't have a system with 4 hyper-threading processors (the i7) to try SL out on, but since my 2 hyper-threading processors are not 'pegging', I would not expect any additional improvement.

One thing to remember is that this is all done with a laptop (Lenovo Edge E420s).  Laptops have very limited cooling capabilities and processor chips are designed and managed with that in mind.  A desktop system with an i5 sandy bridge will have better cooling capabilities and I would expect Intel to take advantage of that and achieve even more performance.

robin

[edit -- oops, I mean to add links to two previous posts relating to sandy bridge and amd's competing fusion.  I'll sneak them in now! ]

http://robin-makingstuff.blogspot.com/2011/05/new-sandy-bridge-laptop.html

http://robin-makingstuff.blogspot.com/2011/06/new-laptops-from-hp-and-amd.html

New Sandy Bridge Laptop

Hi again people!

I do love laptops.  And wireless internet connections, WiFi!  They're such a natural combination that it's hard to think of one without the other. When it comes to running Second Life though, Laptops do have a problem.  The generic low priced Windows 7 laptops that have been generally available miss the mark by a wide margin on 3d graphics performance.

I had this brought home to me as my 'usual' laptop began to die and I had to shift to an emergency backup laptop.  My 'usual' was a laptop with two processors, 2 gigabytes of memory, Windows 7 32bit, and a Nvidia Geforce G 105m Graphics chip. It's one of the versions of the Lenovo Thinkpad SL500.  The emergency backup laptop was about one year newer, it has the two processors, 4 gigs of memory and Windows 7 64 bit and sadly, no graphics chip.  My Second Life performance (Frames Per Second) was not stellar with my usual laptop, but it was mostly ok.  Ok that's pretty subjective, I know. but honestly that's bottom line.  And measured against that same bottom line, the emergency backup laptop was very much NOT ok.  It sucked.

I have been watching the world of Intel and AMD with interest as they added graphics processing to their CPU offerings and so naturally started looking for more information on them as my usual laptop started circling the drain.  Intel's Sandy Bridge series seemed to look right for me and I quickly focused on the i5 over the i3 due to its better graphics processor.  Some benchmark comparisons found on the web put the i5's HD3000 on-chip graphics slightly above the level of nVidia's G 105m - so I visited the Lenovo website, found the Edge E420s, took a deep breath, and plunked my credit card down next to the keyboard of the emergency backup laptop and bought one.

I think that these new Intel an AMD offerings are especially important for Second Life.  Before this, the run of the mill PC, one without a specialized graphics chip, was simply inadequate for a good Second Life experience.  My suspicion was that with these new offerings, that was changing, and a laptop without a graphics chip could provide a decent Second Life experience.

And now, after a few days of experimentation with my new Sandy Bridge laptop, I can report that my suspicions were correct.  While my new laptop will not win any FPS contest anytime soon, it does seem perfectly adequate for a large number of Second Life Sims.  This is good news for Linden Labs.  Soon Intel's and AMD's new cpus will be the dominant offerings in laptops from all manufacturers and LL will find that when someone gives SL a try on a whim their performance will be just fine in most of the Sims they visit.

However, there are a couple of flys in the ointment.  Laptops like to be really really serious about conserving energy and its not unreasonable to have things like processor speed set to the most power-saving mode possible.  Unfortunately, this will not provide a good Second Life Experience.

The second fly in the ointment is the newness of these processors and the likelihood that the user will need to update things like the device drivers, especially those for the the Graphics and Power related things like Intel's Turbo-Boost technology.

My experience with my new Sandy Bridge laptop can help illustrate these problems.

After I had unwrapped my new E420s, plugged it in and turned it on.... it wasn't very long before I had downloaded a new copy of the various viewers I am fond of and started trying them out with Second Life.  I was very, very disappointed in the performance.  The Frames Per Second I was achieving were much lower than what I had achieved with the old dying computer with the Nvidia chip.  This was frustrating and puzzling since the comparisons I had found for the graphics hardware indicated that the HD 3000 was a bit better than the G 105m.  Why was it performing so poorly?

After struggling with it for a while, I decided to see if Intel had a new graphics driver for the HD3000, the 3d graphics portion of the i5 chip.  The date on my driver (found in the Device Manager) was 3/25/11, and the date on the new driver at the Intel website was 4/10/11, just about 2 weeks newer.  Ii downloaded and installed it and quickly found that the performance had improved by 15% to 55% depending on graphics setting and Sim.  This was certainly good news, but still the performance was much lower than I thought it would be.

As I continued setting up the computer, I visited the Power Manager Lenovo provides and looked at the Power Plans. I can't recall what it was originally set to, but I fiddled with it and changed some of the settings in ways I thought reasonable, including setting the CPU performance to be 'Adaptive'.  Then I revisited SL and looked at the FPS again, they had surged dramatically!   Where before, in a lightly loaded Sim, I was getting 14 frames per second, I was now getting over 50!

After rubbing my eyes and testing more carefully.  I found that the thing I changed that had made a difference was the System Settings -> Maximum CPU Performance.  If I set it to Lowest for good power savings, my performance was around 14 FPS and if I set it to Adaptive, it was over 50 FPS and the graphics preferences were set to Medium.

Now please don't get your hopes too high, 50 Frames Per Second is not mylaptop's normal performance in most Sims.  This was a lightly loaded Sim with few avatars present and I was at an altitude with relatively few nearby objects.  But after some Sim-hopping, I've concluded that something around 20 FPS is a pretty reasonable expectation on the medium graphics setting.  It might be 14 or 15 or it might be 25.  And there are also Sims where Intel's new on-chip graphics simply does not keep up... I found one Sim where I was at about 8 fps and moving was like walking in molasses.   This one had almost 50 people in it and was gorgeous with many fine touches - but the cost was walking in molasses.

My conclusion is that the i5 with the HD3000 is a nice processor for a laptop and can run SL comfortably in most cases.

Your conclusion may differ, especially if you frequent one of those Sims that has a huge number of people and a complex set of objects, or if you're seriously into fighting with bows or guns and want to do so at one of the higher graphics settings.  And there is no doubt that adding a graphics chip will make the performance even better.

But that's not the way the average new SL resident will show up, they'll show up with whatever laptop they're currently using. And in the future, more and more will be showing up with Intel's Sandy Bridge and AMD's equivalent..... and that's a good thing!

robin