Pioneer 215-D slow burn problem

[qanda]This thread is about the Pioneer DVR-215D. Click here to see full specs[/qanda]hi, after installing the pioneer 215-D i try some burns, first started with a normal dvds 4 gbs and only for testing i try burning at 8x, but i realize that a normal 4 gb burn take allways 20 minutes burning even selecting 4x 8x 16x … allways take 20 minutes to burn. i strange the fact and then try to burn a DL first started 2x and everything came good, buffer level, device buffer allways at 100% or 99%, then try burn a DL at 4x and 8X and different result, allways take 40 minutes to burn and the device buffer allways jumping and not stay stable, very strange… the fact i came to conclusion is that I can only burn at 2x

this burner is a sata burner so i think that the dma problem doenst apply here but for confirmation i confirmed and DMA is ON in both hardrives
Already try burn with nero and imgburn and same thing happens, the device burn is allways jumping to 32% 24% 100% 29%, allways irregular, the levels stay regular only at burning 2x DL
The burn allways complete ok, at 2X… but never ocurred a error during a burn.
I dont know why but i think its a problem relation to to my motherboard and some incompatibility. my board is a Asus A7V600-X.

SO any ideas i can resolve this thing and finaly burn at the speed i choose?

thanks in advance, any screenshot or information u need just ask.

here it is a log from Imgburn trying to burn DL at 4X:

I 14:39:00 ImgBurn Version started!
I 14:39:00 Microsoft Windows XP Professional (5.1, Build 2600 : Service Pack 2)
I 14:39:00 Total Physical Memory: 1.048.092 KB - Available: 638.116 KB
I 14:39:00 Initialising SPTI…
I 14:39:00 Searching for SCSI / ATAPI devices…
I 14:39:00 Found 1 DVD±RW and 1 BD-ROM/HD DVD-ROM!
I 14:39:18 Operation Started!
I 14:39:18 Source File: C: emp\bioshock[RF]%20Bioshock.dvd
I 14:39:18 Source File Sectors: 3.697.696 (MODE1/2048)
I 14:39:18 Source File Size: 7.572.881.408 bytes
I 14:39:18 Source File Volume Identifier: XGD2DVD_NTSC
I 14:39:18 Source File Volume Set Identifier: 34672923
I 14:39:18 Source File Implementation Identifier: Sonic Scenarist 3.1
I 14:39:18 Source File File System(s): ISO9660; UDF (1.02)
I 14:39:18 Destination Device: [2:0:0] PIONEER DVD-RW DVR-215D 1.22 (D:) (SCSI)
I 14:39:18 Destination Media Type: DVD+R DL (Disc ID: MKM-001-00) (Speeds: 2,4x; 4x; 6x; 8x)
I 14:39:18 Destination Media Sectors: 4.173.824
I 14:39:18 Write Mode: DVD
I 14:39:18 Write Type: DAO
I 14:39:18 Write Speed: 4x
I 14:39:18 Link Size: Auto
I 14:39:18 Test Mode: No
I 14:39:18 OPC: No
I 14:39:18 BURN-Proof: Enabled
I 14:39:19 User Specified L0 Data Zone Capacity: 1.913.760
I 14:39:55 Filling Buffer… (20 MB)
I 14:39:56 Writing LeadIn…
I 14:39:58 Writing Session 1 of 1… (1 Track, LBA: 0 - 3697695)
I 14:39:58 Writing Track 1 of 1… (MODE1/2048, LBA: 0 - 3697695)
I 14:39:58 Writing Layer 0… (LBA: 0 - 1913759)
I 14:57:26 Writing Layer 1… (LBA: 1913760 - 3697695)
I 15:13:58 Synchronising Cache…
I 15:13:59 Closing Track…
I 15:14:03 Finalising Disc…
I 15:15:30 Exporting Graph Data…
I 15:15:30 Graph Data File: C:\Documents and Settings\João\Application Data\ImgBurn\Graph Data Files\PIONEER_DVD-RW_DVR-215D_1.22_DOMINGO-18-DE-JANEIRO-DE-2009_14-39_MKM-001-00_4x.ibg
I 15:15:30 Export Successfully Completed!
I 15:15:30 Operation Successfully Completed! - Duration: 00:36:11
I 15:15:30 Average Write Rate: 3.625 KB/s (2.6x) - Maximum Write Rate: 4.173 KB/s (3.0x)