25 December 2015

Trip Down Memory Lane

I got into building my own computers when Nvidia announced support for GPGPU on their G80 chipset (think GeForce 8800GTS/GTX/Ultra). Good times in 2008.

My one-upping started after this fellow rubbed his Core i7-920 in my Core 2 Quad Q9550's face. Game on! But really, I didn't have the funds or the knowledge to beat that.

Then a good friend Bayley showed up at MIT, and things got serious reasonably fast. In particular, my upgrade path looked something like this:
  • Core 2 Quad Q9550 4-core/8GiB DDR2
  • Some Intel Xeon W35xx 4-core/24GiB DDR3
  • 2x Intel Xeon X5650 6-core/24GiB DDR3
  • 4x AMD Opteron 6164 HE 12-core/128GiB DDR3 ECC
Then Bayley and I both realized that we had to switch to rackable computers for any sort of ease in managing hardware. I took a break from single-image systems and built half a blade server:
  • 2x Intel Xeon L5320 4-core/8GiB DDR2 FB-DIMM
While Bayley got a Sun Box®:
  • 8x AMD Opteron ??? 4-core/128GiB DDR2 ECC
In a valiant attempt to dethrone me, he patched the Sun's BIOS with the microcode for hex-core CPUs, but the computer only recognized one core of one processor of the eight that he put it. Much wow.

My AMD box cemented 1st place in sheer awesomeness for student-owned computers for a little over a year, until Bayley discovered mainframes on eBay:
  • Some IBM thing with 16x Intel Xeon E75xx 6-core/256GiB DDR2 ECC
Mind you, I have cemented awesomeness density, since my AMD box fits perfectly in 1U, while Bayley's monstrosity needs 16U, and a whole lot more power. :-) Not to mention that it blew a circuit breaker while trying to install Ubuntu…

Leave it to me, my worst enemy, to dethrone myself. I wanted to repackage the AMD box into a legitimate 1U chassis that I found on eBay for not too much money, since it had sat on a piece of cardboard (for insulation!) atop the dorm dresser. After the computer happily booted in the chassis, I jiggled one of the unscrewed heatsinks and shorted the motherboard. A nice spark flew from a voltage regulator to the copper heatsink and poof!

gg no re Bayley


There's also a GPU story, which I shall not neglect. I went to MIT with my trusty aforementioned 8800GTS 320MB. A few swapfests later, Bayley wound up with a quartet of GTX 460s. It was mainly used for benchmarking Holy Balls, a demanding multi GPU raytracer, and got really toasty after a while. Good old Fermi.

The cryptocurrency scene started getting traction with the advent of profitable scrypt-coin mining. AMD cards were far superior in hashes/watt and competent in hashes/sec. Bayley got his hands on a few AMD 7850s, the preferred mining card, among other cards. I went extra long and got 11 cards from various sources (newegg, eBay, etc) since retailers caught on to the mining demand. Luckily I was able to dump my cards at cost (after eBay commission) after Mt. Gox blew and before everyone else wanted to dump their cards. Bayley kept mining, and even upgraded to 7950s as well as a 6990 when prices decreased and good deals appeared.

But wait, I'm back! I had the privilege of acquiring a new Mac Pro (affectionately known as the "trash can") with dual AMD D700 graphics cards. For all intents and purposes, they are two workstation grade cards (think neutered W9000s), each with 6GiB VRAM. So I can confidently say that I retake the GPU crown.


Meanwhile, with the abundance of swapfests at MIT, Bayley acquired multiple storage nodes for not too much money (and the networking infrastructure to back the system). To top that, he accidentally won half an SGI Altix and soon to be the glorious 1TiB of RAM on eBay.


GiB and TiB stand for Gibibytes and Tebibytes, because I'm anal and care about these distinctions.

20 December 2015

Car Mods III

After my first track weekend, I've learned a bunch about driving and a few things about mods. I'll start with mods since the list is shorter:

One of my instructors had a 991 C2S with Michelin Pilot Sport Cup 2s (R-compound tires, or semi-slicks). He claimed he could easily do 2:08s, which is about on pace with a 997.1 GT3 RS. I'm sure he was also running track brake pads, since R-compounds generate more heat than street tires. If I went this route, then my upgrade path would look like:
  1. Brake pads
  2. 19" rims
  3. Michelin Pilot Sport Cup 2s

The unfortunate thing about the Pilot Sport Cup 2s is that Michelin does not make them for my 18" rims (235/40 front, 265/40 rear), but they are available for the 19" rims (235/40 front, 295 or 305/35 rear). Then that's at least $1k for the rims, and $2k for a set of tires after tax. I also looked into Pirelli's P-Zero Trofeo Rs, which are available for my 18" rims and cost only $1.4k a set after tax. As for functional differences between the two tires, the Michelins offer less peak grip at 1.6g vs 1.8g, but the transition to sliding is more gradual at the limit than the Trofeo Rs. As for practical considerations, the Michelin has more treadwear, and has a reasonably long life expectancy. It is classified in a lower penalty group in autocross car classification.


I had one last track day this season with Hooked on Driving (HoD) at Thunderhill again. I improved my exit speeds on average, and greatly improved my entry speeds on T10 and T11. Overall, I was able to cut my best time by 6 seconds down to 2:21.xx. A huge difference between the Porsche Club (PCA) and HoD is that HoD puts turn-in and apex landmark cones on the track, while PCA doesn't. I agree with PCA that cones should not be present so that drivers develop their own references instead of relying on a temporary object that can get knocked out of position. However, they're really helpful and reinforced several of the turn-in points for me.

Carrying more speed through turns means that I'm falling out of my seat more and more and devote more energy to bracing myself. In particular, my left leg was super sore by the end of the day from standing on the dead pedal in turns. I've been researching various aftermarket race seats, specifically the halo-style seats (wraparound head support). Fitment is done mostly by hip width, so the driver is held securely in place, even with a standard seatbelt. A decent seat is also only $1k, and can be swapped into another car if I choose to run another vehicle.

I think I'll stick with the 3-mile Thunderhill course for next season, and explore other local tracks for the 2017 season, and at the earliest, the end of 2016 season. At my HoD day, I ran with their B group  (intermediate) for two sessions with my instructor, and felt pretty comfortable. I'm running at a mid-pack or slightly below median pace. With a bit more practice, I should be high B by the end of 2016, perhaps low C. For now, I'm hesitant about point-by passing nearly everywhere because it sounds scary, and am afraid that other people in the run group will dislike my conservative point-bys.

As for brake pads, I don't see any reason to upgrade. The car has 0.5g of deceleration during hard braking, and I haven't had any heat issues yet. Given that I won't upgrade the engine power anytime soon (car is plenty fast), I won't need more braking force to compensate. Same for rotors -- larger rotors in theory can better dissipate heat due to more surface area, and lots of heat may cause rotor warping, which also hasn't happened yet.

I will keep the suspension stock as well for the upcoming season. When I get better at discerning different adjustments, I'll consider adding a GT3 sway bar and adjusting camber/toe.


That's all for now. Here's to a safe and fun 2017 season!