Bad transmission rate

Hi,

I've installed a OpenBSD 3.8 box and have some strange rate problems  
when copying data over the network with scp. For hardware specs look  
at the end of the email for a dmesg output.
Ok here is the problem. The networkcard is a 10/100Mbit connected  
with a couple of PCs through a 10/100MBit switch.
When I try to copy some data over the network with scp I get the  
following rates:
- copy data from OpenBSD to a Debian machine: "scp user@obenbsd:data ."
  output: "data 100%  100MB 483.0KB/s   03:32"
- copy data from OpenBSD to a Mac: "scp user@openbsd:data ."
  output: "data 1% 1856KB  57.4KB/s   29:12 ETA"
- copy data from Debian to a Mac: "scp user@debian:data ."
  output: "data 100%  100MB   7.1MB/s   00:14"

As you can see the transmission of a file with a size of 100MB is  
about 480KB/s from a Linux-Client and 60KB/s from a Mac-Client. The  
Problem has to be an OpenBSD-Side. Because when you transfare the  
data from Debian to Mac or reverse I get a transmission rate of 7.1MB/ 
s. I've searched the mailinglist etc. but didn't find a right  
sollution for this problem. Does anybody has an idea?

-Stefan


$ dmesg
OpenBSD 3.8 (GENERIC) #138: Sat Sep 10 15:41:37 MDT 2005
    deraadt@i386.openbsd.org:/usr/src/sys/arch/i386/compile/GENERIC
cpu0: Intel(R) Pentium(R) 4 CPU 1500MHz ("GenuineIntel" 686-class)  
1.50 GHz
cpu0:  
FPU,V86,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,PGE,MCA,CMOV,PAT,PSE36, 
CFLUSH,ACPI,MMX,FXSR,SSE,SSE2,SS,HTT,TM
real mem  = 1072472064 (1047336K)
avail mem = 972001280 (949220K)
using 4278 buffers containing 53727232 bytes (52468K) of memory
mainbus0 (root)
bios0 at mainbus0: AT/286+(00) BIOS, date 08/12/04, BIOS32 rev. 0 @  
0xf0010
apm0 at bios0: Power Management spec V1.2
apm0: AC on, battery charge unknown
apm0: flags 30102 dobusy 0 doidle 1
pcibios0 at bios0: rev 2.1 @ 0xf0000/0x10000
pcibios0: PCI IRQ Routing Table rev 1.0 @ 0xf5a40/192 (10 entries)
pcibios0: no compatible PCI ICU found: ICU vendor 0x1106 product 0x3227
pcibios0: Warning, unable to fix up PCI interrupt routing
pcibios0: PCI bus #1 is the last bus
bios0: ROM list: 0xc0000/0xd000!
cpu0 at mainbus0
pci0 at mainbus0 bus 0: configuration mode 1 (no bios)
pchb0 at pci0 dev 0 function 0 vendor "VIA", unknown product 0x3168  
rev 0x82
ppb0 at pci0 dev 1 function 0 "VIA VT8377 PCI-PCI" rev 0x00
pci1 at ppb0 bus 1
vga1 at pci1 dev 0 function 0 "ATI Radeon 9200 SE 2nd" rev 0x01
wsdisplay0 at vga1 mux 1: console (80x25, vt100 emulation)
wsdisplay0: screen 1-5 added (80x25, vt100 emulation)
"ATI Radeon 9200 SE" rev 0x01 at pci1 dev 0 function 1 not configured
pciide0 at pci0 dev 15 function 0 "VIA VT8237 SATA" rev 0x80: DMA
pciide0: using irq 10 for native-PCI interrupt
pciide1 at pci0 dev 15 function 1 "VIA VT82C571 IDE" rev 0x06:  
ATA133, channel 0 configured to compatibility, channel 1 configured  
to compatibility
wd0 at pciide1 channel 0 drive 0: <WDC WD800VE-00HDT0>
wd0: 16-sector PIO, LBA, 76319MB, 156301488 sectors
wd0(pciide1:0:0): using PIO mode 4, Ultra-DMA mode 5
atapiscsi0 at pciide1 channel 1 drive 0
scsibus0 at atapiscsi0: 2 targets
cd0 at scsibus0 targ 0 lun 0: <HL-DT-ST, DVD-ROM GDR8162B, 0015>  
SCSI0 5/cdrom removable
cd0(pciide1:1:0): using PIO mode 4, Ultra-DMA mode 2
pcib0 at pci0 dev 17 function 0 "VIA VT8237 ISA" rev 0x00
vr0 at pci0 dev 18 function 0 "VIA RhineII-2" rev 0x78: irq 11  
address 00:11:2f:bc:c5:12
rlphy0 at vr0 phy 1: RTL8201L 10/100 PHY, rev. 1
isa0 at pcib0
isadma0 at isa0
pckbc0 at isa0 port 0x60/5
pckbd0 at pckbc0 (kbd slot)
pckbc0: using irq 1 for kbd slot
wskbd0 at pckbd0: console keyboard, using wsdisplay0
pcppi0 at isa0 port 0x61
midi0 at pcppi0: <PC speaker>
spkr0 at pcppi0
sysbeep0 at pcppi0
lm0 at isa0 port 0x290/8: W83627THF
npx0 at isa0 port 0xf0/16: using exception 16
biomask f7fd netmask fffd ttymask ffff
pctr: user-level cycle counter enabled
dkcsum: wd0 matches BIOS drive 0x80
root on wd0a
rootdev=0x0 rrootdev=0x300 rawdev=0x302