The New Nvidia Video Drivers 335.23 Unlock GTX 750 Ti GPU Overclock

10 Mar
2014

new-video-drivers-gtx-750-ti-overclock

Nvidia has just released new GeForce video drivers version 335.23 WHQL that removes the limit of +135 MHz maximum overclock for the GPU that was previously available on all GTX 750 Ti video cards. This allows or more serious overclock of the GPU and thus for increased performance in terms of hashrate if your GTX 750 Ti video card is able to handle the extra overclock of the GPU. We have already tried the new driver on our reference design GeForce GTX 750 Ti board and MSI Afterburner now allows us to go to up to +1000 MHz on the GPU unlike being limited to maximum +135 MHz with the older drivers. The maximum we were able to get our card working stable at was +175 MHz on the GPU that has allowed us to squeeze a few more KHS out of the video card. Note that we have the video card flashed with modified BIOS with increased power target limit, if you do not modify the video BIOS even if you set he GPU frequency higher you might not be able to get your hashrate increased due to reaching the power target limit.

– To download and try the new Nvidia GeForce video drivers version 335.23 WHQL…

The Power Consumption of a 6-card Mining Rig using GeForce GTX 750 Ti GPUs

10 Mar
2014

six-gpu-rig-gigabyte-geforce-gtx-750-ti

We have already published some interesting findings about the power usage of the new GeForce GTX 750 Ti graphics cards when used for crypto mining and recently we have built a 6-card GTX 750 Ti mining rig. We have taken some time to also measure the power usage of the individual cards as well as the total power usage of the whole system in order to give you some additional details about what you can expect in terms of power consumption from such a mining rig. We have used Gigabyte GeForce GTX 750 Ti video cards (N75TOC-2GI) that do have an external onboard PCI-E power connector and we started by measuring the total power that goes to a single video card both trough the PCI-E slot as well as through the external PCI-E power connector with the help of a watt meter that is attached directly to the power lines going to the video card (using a powered extender).

gtx-750-ti-power-usage-pci-e-power

As you can see on the photo the total power used by the video card is about 31W (with the card running at +135 MHz for the GPU and + 610 MHz for the video memory). Note that this power measurement is on the 12V line from the PSU going to the video card, so it does not take into account the power efficiency of the power supply and as a result the total power used by the video card from the mains will be higher by something like 15-20% (depending on the PSU). Note that we have used a powered PCI-E extender with USB 3.0 cable for the data lanes. This extender takes all the power provided to the PCI-E slot of the video card through a 4-pin molex connector and supplies both the 12V and the 3.3V power that the card uses drawing only power from the 12V line (there is a voltage regulator to output 3.3V from the 12V input on the extender’s board). So what the wat tmeter shows is the total power going from the PSU to the video card and in the case of the Gigabyte GTX 750 Ti it was 31W. Again the total power usage from the mains will be higher as this measurement does not take into account the power efficiency when converting 220V/110V to 12V.

gtx-750-ti-power-usage-5-6-cards

So what is the situation with the total power usage per GTX 750 Ti video card from the mains? The easiest way to check that is to measure using a watt meter connected between a power socket and the power supply of the computer the total power consumption of the system with 6 cards and then disconnect one card and to measure again. The difference we got using this method was about 79W, though this is not for the video card only as it also affects a bit the overall power consumption of the whole system. Also note that the measured 374 Watt for the 5-card and 453 Watts with the 6-card setup are with the video cards overclocked to +135 MHz/+610 MHz. The results we’ve got with the cards running at the stock frequency were 367W with 5-cards and 432W with 6 cards or a 65W difference per card (total power used from the mains). This difference of 14 watts between stock and overclocked frequencies brings roughly about 40 KHS more in terms of hashrate for Scrypt mining (per card). Have in mind that our power supply used had an efficiency rating of about 80-85%, so this means that 15-20% of the total power used at the mains is actually wasted in the conversion between 220V/110V and 12V.

Another interesting thing that we have noticed while testing the power usage and overclocking capabilities of the 6-card GeForce GTX 750 Ti mining rig was the total power consumption that we got for the system with the power target limit changed from the standard setting of 38.5W to the 65.5W. The watt meter showed an increase of power from the 453W with the 38.5W power target limit to 556W with the 65.5W power limit – about 100W increase with the same operating frequencies with a slight increase in performance of about 90 KHS total from the 6 cards or roughly a bit over 1W per KHS and in our opinion this is not worth the extra increase in power usage, so raising the power limit may not always be a good idea!

Official Statement From Bit Mining About Current Technical Issues

10 Mar
2014

bit-mining-cloud-mining-service

The Bit Mining cloud mining service for LTC and BTC is still not back to its normal and fully functional state, though things are slowly getting back online, but it could take some more time. Meanwhile there is an official statement from the guys behind the cloud mining services that reveals some more details on what has actually happened in the last few days and why is the service still not fully operational and back online…

Hello Bit-Miners,

We apologize for the unintended interruption in service; let us bring you up to
speed on the current situation over at Bit-Mining

Over the last few weeks, we have suffered a series of attacks against our
pools by a would-be hacker. This will explain the frequent and clustered pool
down times we have been experiencing; we have been doing our best to guard
ourselves against these DDOS attacks.

In the past few days however, the actions of our assailant have escalated, with
ransom demands and threats that have ultimately culminated in an intrusion
attempt on our server. Thanks to the valiant efforts of our TECHs, and security
considerations already in place, we were able to fend of this attack with
minimal damage. Our wallets were completely unaffected by the attack;
however, we have experienced corruption of our trading database and are
working to restore it to its pre-intrusion state. Let me clarify; NO USER FUNDS
OR ASSETS HAVE BEEN AFFECTED. ALL MINING HARDWARE (that represents
your Purchased GHs/KHs) IS ALSO SAFE. Because of the corruption of the
trading database, we are suspending the Trading feature until we can get
everything sorted out with certainty.

If you had a BTC/LTC balance before we experienced down time; it should be
accurately reflected in your account balance currently and available for
withdrawal. We are expediting withdrawals for the time being to alleviate user
concerns. However, due to the way the database has been reconstructed,
there may be a few users with incorrect monetary balances; simply contact us
at support@bit-mining.co so that we can take an individual consideration of
your account and make it whole. This is also true for GHs/KHs balances, most
should be correct but there may be a few users with unique circumstances.
Mining power that is in pending orders will also be restored once we resume
trading. To all users having issues with referral counts, this is to be expected
and will be resolved soon. If you have an issue after that just contact us and
we will sort it out.

If you cannot regain access to your account, first attempt to reset your
password.

All withdrawals should have been processed before we went offline; and we
also have a record of all requested and satisfied withdrawals; if you are
currently awaiting one check to make sure you haven’t received it. If you still
haven’t received one that you know you requested, send an email to
contact@bit-mining.co with subject STUCK WITHDRAWAL, we will patch you
up.

Also, to ease concerns about mining payouts, no user has been paid out since 
3/07/14 (as we have been down since then), but everyone will be reimbursed
for Purchased GHs/KHs payouts whether or not they were in orders at the
time; we will not penalize the user for the inability to gain account access
during our downtime.

We sincerely apologize for any inconvenience this outage may have caused our
users.  We give our users our assurance that we will investigate each and
every user issue until eventual resolution; but we ask  that users hold non-
account access and withdrawal related issues until after we resume trading.
The maturity of our users about this matter is greatly appreciated during this
difficult time. We still remain committed to providing a superior cloud mining
experience with the most competitive pricing we can provide. We hope that
users observe our handling of this situation as an indication of our dedication
to this project.

As soon as I get a more precise ETA on trading being re-enabled from our
TECH department; I will update everyone via email and forum post. Chat
restrictions are lifted in order to facilitate user issue resolution, and I will be
available in site chat to answer any individual user questions.

If you have any additional concerns or questions please don't hesitate to
contact us. I apologize again for the hassle this has caused everyone.

BMC Support

– For more information about the Bit Mining BTC/LTC cloud mining service…

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